Posted on June 30, 2026June 30, 2026 by Mel — Leave a comment

Minolta X-700 Frame Counter Repair Guide

Minolta X-700 Frame Counter Repair:– One of the most common faults with the Minolta X-700, X-500 and X-300 cameras is the frame counter failing. This is due to the small plastic stop on the counter disk shearing away. With the stop stud gone the frame counter spring will lose tension and the counter becomes useless.

This is a simple guide to repairing the X-700 frame counter and is a small sub-set of the X-700 Servicing Guide we created some time ago.

As a note this is applicable to all X-700, X-500 and X-300s but only the X-700 will be described here. The X-700 is almost identical to the X-500 but the X-300 does have a different top cover.

This guide is not applicable to the XG-M which uses different components and does not suffer this issue as its frame counter is made of metal rather than plastic.

Before starting read through the entire instructions so you know what you will need to do. Also, to work on Japanese cameras you really need JIS drivers. The screws used in these cameras look like a Philips head but have a slightly different profile. A Phillips driver may work but can damage the finish of the screws. Finally – take your time – there are no prizes for being the fastest in camera repair and a rushed job will often lead to creating more problems than you are trying to solve.

Minolta X-700 Frame Counter Repair: Step 1 – REMOVING THE TOP COVER OF THE X-700

Minolta X-700 Frame Counter Repair - Removing the X-700 rewind capstan

Remove the JIS screw from the top of the rewind crank/capstan and pull the capstan free.

Minolta X-700 Frame Counter Repair - Securing the film spool

Replace the capstans screw, this will stop the film spool dropping down inside the camera by accident. The screw head will block the spindle from falling down inside.

Removing the X-700 Exposure Compensation Ring

Set the ASA dial to 200 and to set the exposure compensation to Zero. On this camera someone had replaced it incorrectly causing it to jam completely.

Under the capstan is a slotted retainer. These vary camera to camera. Some are metal and some are plastic. Most have slots but some don’t.

If slotted you can apply a lens spanner or alternately use a rubber bung. This fitting is not usually tight but age and dirt ingress may cause it to stick. If it doesn’t move easily apply a little Isoprop and try again.

Washer under the exposure compensation retainer

Under the slotted retainer there is a sprung washer. Remove this and then remove the ASA and Exposure compensation dial.

Be careful – under the dial there is a thin plastic washer. Note its position and remove this. Treat it carefully and avoid damage as this is what smooths the feel of the ASA ring.

Note the position of the two plastic prongs that extend from below the top cover. These connect to the ASA and the exposure compensation dials.

Most X-700s have a slotted retainer on top of the advance lever but some have a smooth sided one. In either case it’s best to use a rubber bung to remove these in order to protect the finish.

They can be tight so a small dab of Isoprop will generally help. If not and you need to resort to a lens spanner to get this turning use some tape over the retainer to protect its finish.

The retainer is a standard thread.

With the retainer removed the advance lever MAY be free. Some X-700s have a spring underneath and some later ones have a sprung washer.

If it has the spring observe the cut out in the advance lever and gently unhook the spring and the remove the advance lever.

If the camera has a spring this can be removed – if it has washer remove that as well.

The spring is located into a hole on the camera body top cover so will need to be turned slightly to disengage it.

Remove the slotted nut under the film advance. This is a standard thread. This is usually quite tight and you will need a lens spanner capable of quite a small nut.

Set the shutter speed/mode dial to ‘P’ this will make life easier when you come to replace it and allow for easy testing.

Unscrew the trim ring around the shutter button. This is not usually tight. Normally a cocktail stick is all that’s needed. The thread is a standard thread.

Using a soft wooden stick will prevent the finish being damaged.

As you unscrew the retainer watch out. The spring under the shutter button is quite powerful and can propel it out of the camera.

With the shutter button and its retainer removed the shutter speed dial will simply pull away.

Removing the screw to the left of the X-700 body

Remove the JIS screw on the cameras left shoulder…

Removing the screws wither side of the viewfinder

…and the two screws to the side of the viewfinder.

Removing screws below Minolta nameplate on X-700

Remove the two JIS screws under the name plate and pull the name plate free.

Apply some low tack tape to the mode selector lock button and the camera top. This will retain the small button and prevent loss. This can fall into impossible to reach places so its a simple method of making sure this process goes without further issues.

The camera top can now be lifted away. Do not apply any stresses to this as there are a number of wires between the hot shoe, the sounder and the camera circuit board below. Make a note of where the wires go as these can easily detach from the circuit board without much effort.

As the top comes away from the camera watch out for the small button and also for the viewfinder surround. These are both free once the top is removed.

Minolta X-700 Frame Counter Repair:- Step 2 – REPAIRING THE X-700 FRAME COUNTER

With the cover removed you now have access to the frame counter mechanism. The pictures below show the basic parts of the mechanism. The most usual failure is the stop stud breaking away from the counter disk OR the spring that manages the counter disk slipping away from its anchor point. The following section will show how to deal with both of these issues.

This X-700 has suffered a broken Counter Stop Stud. A previous repair done by someone else has failed.

The previous repair was to try and glue the stud into place. This is almost never successful.

Typically the stud is lost inside the camera (it’s quite small) and even if it can be recovered getting it glued back in place seldom works. The surface of the counter dial makes glue ineffective.

First off gently pull the film safe indicator lever back and wedge it so that it stays clear of the counter dial.

Grip the index plate with some tweezers or fine pliers and lift it slightly so that its locating hole clears the boss and then pull it away.

The counter disk can now be lifted off, make sure to watch out for the spring which will be connected to the lower plate of the camera.
X-x00 models all seem to have this located in different places and the service manuals are not clear. In this case someone had hooked it to the edge of the plate shown which is NOT correct.

Exercise caution as the spring is relatively weak and fragile.
Note how one end of the spring has a hook that connects it to a slot in the counter dial.

Here is the counter dial removed with its spring.

The spring has been removed from the counter dial for safety.

The counter disk and index plate for marking

This part is easier done on the camera but in this case it was not possible.

What you need to do is to align the counter disk and the index plate such that the index plate marker indicates zero (S) and then make a mark where the edge of the index plate is in relation to the dial near the ’34’ partion of the dial.

This will be the location of the stud. Eg the place where the stud contacts index plate and stops the dial turning any further.

You need to drill a very small hole in the thinnest part of the counter disk. The should should be about level with the centre of the ‘34’ marking and about midway between the center of the disk and the edge of the ‘3’.

The hole needs to be slightly smaller than the diameter of a medium paperclip. The dial is relatively soft plastic so I usually use a small awl or darning needle to drill through with.

This is easy if the broken/missing stud has left a trace of where it was.

Here’s the paperclip being sized.

It needs to be a good tight fit.

The paper clip glued to the X-700 counter disk

Cut a section of paper clip off and use a strong epoxy to glue into place.

I usually use Araldite Rapid for this repair. It’s a two part epoxy.

It takes around 24 hours to come to full strength and MUST be very throughly mixed for it to get the best strength.

The height on the top side of the counter disk doesn’t matter at this point so long as the glue join is clean but at the base of the the disk must be flush or nearly flush or any obstruction will foul the spring when the disk is replaced.

Do not rush this part of the job – the epoxy glue can take up to 24 hours to set off fully.

Once the glue is fully dry replace the spring to the counter dial.

Push the film safe indicator out of the way….

Open the fimm door and replace the counter disk

Open the film door and replace the counter dial making sure it seats properly.

Notice the paperclip repair is still very tall. There is a reason for this as you will see later.

To get the counter disk seated you may have to gently press the white counter actuator back slightly. It should engage with the gear teeth under the counter disk.

Check the spring under the counter disk is not fouled or caught on either the washer below the counter disk or any other obstruction.

Hook the free end of the spring of the counter disk as shown below. Minolta changed location of this over time. The two most common positions are shown.

Tensioning the X-700 Counter Disk Spring

Close the film door and apply 2-3 turns of the counter disk in the direction shown to tension the spring.

Make sure that you do not over tension the spring – there has to be enough slack to allow the camera to count up to slightly beyond ‘36’ on the dial.

The Minolta service guide says 3-4 turns but I have yet to see an X-700 where beyond 2 turns is possible.

You will need to push the film safe indicator out of the way to do this.

Reinstall the index plate making sure it’s fixing hole is locked over the boss and that the ‘C’ shape of the plate is in the lowest position located into the groove around the film fork guide.

You can now open the film door and check that the counter returns to zero (S) when the door opens.

Close the film door and double check the counter is counting upwards as you advance – you will need to apply the advance lever to do this. Check the counter is operating correctly.

Using some cutters crop the end of the paperclip rod down.

It must be no higher than the height of the film safe lever or else it will foul on the top cover.

STEP 3 – REPLACING THE TOP COVER OF THE X-700

Align the exposure compensation and ASA rings.

Assuming the camera was set to ASA 200 and exposure compensation was set to Zero the two prongs on the plastic parts will align almost perfectly with the strap lug (A).

Note that the cut out on the clear plastic part will align and fit to the sprung contact at (B).

Replace the shutter selector lock button into place and apply some low tack tape to keep it in position.

Use some low tack tape to hold the shutter selector lock button in place as you replace the top cover.

Replace the viewfinder surround onto the camera and then replace the camera top.

Take care not to trap or break any of the wiring as you replace the top cover.

Replace the screw to the camera shoulder.

Replace the screws either side of the viewfinder.

Replace the slotted nut onto the film advance lever spindle. Tighten down to hand tight and then add a small extra tension. Be careful – you don’t want to strip the threads.

Re-install the spring making sure that one end of the spring is located into the slot on the top plate.

Place the advance lever above its location and make sure that the other end of the spring is located into the slot on the advance lever.

Tensioning the spring to the X-700 advance lever

You now need to rotate the advance lever 360 degrees around the advance spindle to tension the spring before seating it onto the spindle.

When seating the advance lever make sure the spring does not rise up and get trapped onto the top of the spindle.

This is easily one of the most frustrating jobs on an X-700 so take your time and remember patience is not just a virtue – when it comes to camera repair it’s a necessity.

Replace the advance lever top cover and secure using a rubber bung or lens spanner.

Test if the advance lever is moving easily and returning quickly. If the spring has been trapped it will have a nasty resistant feel and will not snap back into place.

Replace the shutter speed selector and shutter release. It is assumed this was left on the ‘P’ setting prior to disassembly.

Replace the chrome retainer ring. This does not have to be much more than finger tight.

Replace the thin plastic washer under the ASA dial.

Check that the posts on the ASA rings underneath are still aligned and carefully replace the ASA dial making sure that the posts on the internal fittings align with the cut-outs on the back of the dial.

Replace the washer on top of the ASA dial.

Replace the slotted retainer using either a lens spanner or a rubber bung.

DO NOT OVERTIGHTEN THIS – if this is too tight it will give the ASA dial and the exposure compensation a very over stiff feel.

Replace the rewind capstan – you will have to unscrew the screw from the film spool.

DON’T let the film spool forks drop inside the camera.

It’s smart to do this with the door open so you can push the film forks upwards and stop them dropping inside.

Replace the front name plate and secure with the two JIS screws.

I hope this Minolta X-700 Frame Counter Repair guide will have helped return your camera to fully working and may you enjoy many years of happy shooting with this classic 1980s 35mm

If you have enjoyed this Minolta X-700 Frame Counter Repair guide and want to know more about servicing the X-700 then check our complete service guide located HERE

Thank you all so much for visiting our site and for the great feedback. This site is also a labour of love and we are passionate about keeping it alive for as long as possible. If you found this site/page helpful why not buy us a coffee to say thank you and say hi. We love to hear how you get on with our tutorials and articles. Mel xx

Repair Nikkor-Q 135mm f3.5 NAI Lens

A short guide on how to Repair Nikkor-Q 135mm f3.5 Lens.

Nikon has been making the 135mm f3.5 lens since around 1959. The first version was around from 1959 to 1969 and was called the Nikkor-Q. The original lens had 4 elements in 3 groups and is easily recognised as its focal length on the beauty ring is in cm rather than mm and reads 13.5cm. The mount type was Nikon F Non-AI.

The slightly revised version ran from 1969 to 1979 using the same 4 elements in 3 groups design and is easily identified by its focal length being in mm as shown on its beauty ring. Mount types for these was Nikon F and non-AI but some versions would have been converted to AI either by the factory or aftermarket technicians.

Nikon produced many different versions of this lens but across its lifespan there were only 3 optical variations although coating techniques were improved over time and the lens was produced with two different diaphragm mechanisms – one with 6 blades (this one) and a later version with 7 blades. This guide covers and early version believed to be from the 1959-1969 version as it carried the Nippon Kogaku name rather than Nikon but all early versions will be nearly identical. Nikon dropped the NK name around 1966 but some lenses continued to be badges as NK as late as 1970.

It should be noted that Nikon struggled with 35mm SLR lenses in the early period and lenses from this era can show a lot of internal messing about with additional holes, slots and scriber markings all done by the factory as Nikon tried to get to grips with the design and production issues.

This lens was acquired is very poor condition and had a very loose focus due to the focus helicoils having dried out, vaporised grease in parts its shouldn’t be and a poor feel to its aperture control ring which was spongy and lacking in ‘click’.

NOTES ON WORKING ON THE NIKKOR-Q 135mm f3.5
The Nikkor-Q 135mm is a relatively easy lens to work on for the most part but like many vintage lenses it has its foibles. It is absolutely critical with this lens that you mark the helicoils for infinity focus and separation points. Failure to do so will result in a lot of issues during reassembly.

The internal construction is very solid but it does have its oddities compared to some other manufacturers evidence of the struggle Nikon were having adapting to 35mm SLRs.

You will absolutely need a good set of screwdrivers for this lens that are correctly sized. Attempting this repair with amateur tools will result in problems. I would recommend the pro-set of screw drivers from Polar Bear Camera together with the special Nikon driver for removing Nikon slotted screws on the lens mount if the lens has slotted screws.

Screws on Nikon lenses are typically hard to deal with, Nikon used a lot of thread lock and lacquer on the screws. You will need Isoprop and Acetone to remove these or use the tip of a soldering iron to head the screw head which will weaken the thread lock.

Be careful when tightening screws. Much of the lens is composed of a light alloy and threads can be stripped easily. You should apply no more than hand tight when holding the screwdriver between thumb and forefinger.

Nikkor-Q 135mm f3.5 NAI Lens – Stripping Down

Set the lens to infinity. As you work on the lens at the initial stages make sure that the infinity position is retained. Like many old lenses you will most likely find the lens comes to infinity just at the start of the infinity mark and focuses slightly past infinity.

This is quite common as the manufacturers built in an allowance for glass expansion.

Nikkor-Q - 135mm f2.8 Lens Removing the focus barrel

Remove the 3 small screws from around the lens focus barrel. These can be very well stuck down. Try to avoid using acetone for these as it will remove the painted finish. Dab with Isoprop and give the Isoprop at least 15 minutes to get to work.

A correctly sized screwdriver will help you avoid damaging the screw heads. With the screws removed simply pull the focus barrel free.

Nikkor-Q - 135mm f2.8 Lens Removing the filter ring

Remove the small grub screw from the filter ring and then unscrew the filter ring.

With the filter ring removed note the small hole that the grub screw fitted into. This is critical on this lens as the only thing holding all of the optical assembly in place is the filter ring which in turn is reliant on this grub screw.

Some versions of the lens will have two additional screws which retain the optical assembly which need to be removed. They were not present on this version.

Nikkor-Q - 135mm f2.8 Marking the helicoil position for infinity

This was taken as the optical assembly was removed – you can see the helicoils have been marked for their infinity position with a scribe mark.

On lenses of this vintage this is absolutely critical and is generally good practice with any lens.

Nikkor-Q - 135mm f2.8 removing the optical assembly

With the filter ring removed, and the two small retaining screws if present, removed the entire optical assembly will now pull free from the lens body.

Nikkor-Q - 135mm Lens the optical assembly

The ‘core’ of the lens is the optical assembly which includes both front and rear optical blocks plus the diaphragm mechanism. On this lens the core element was dirty on the outside only – internally the optics were pristine with no dirt or fungus present.

Its never smart to start messing with optics that are already perfect so this will just have an external wipe down to remove dust and dirt.

135mm Nikon f3.5 - Removing the sleeve screws

Remove the three sleeve retaining screws around the sleeve.

Slip the sleeve off of the lens body.

Nikon 135 Q Series lens - removing the aperture ring

Scribe a line where the aperture ring ends – this will aid in re-assembly later. Then remove the aperture ring screw.

This screw activates the inner aperture control ring which you will see later.

Unscrew the aperture ring.

You can see in this picture the scribe mark indicating where the ring fitted.

Remove the screws securing the mount ring. For dealing with Nikon screws apply either some Isoprop or Acetone to soften the thread-lock OR use the tip of a soldering iron to heat the screws up.

The special Nikon driver bit sold by Polar Bear Camera will make this a lot easier and avoid chewing the screw heads.

The mount plate simply lifts off. There are no mechanics to it at all as all of the aperture functions are controlled by the lens body and the core assembly. Note though the slot for the aperture stop down lever.

From this point on exercise mindfulness – its very easy to sit the lens down on its base and apply pressure and break the aperture stop down lever.

Nikon 135mm f3.5 Lens - the aperture spring

Due to the heavy oil contamination inside the lens body the interior of this lens will need a lot of cleaning so I am going to take out the aperture control ring.

To make this easier I will remove this small spring for the stop down lever. The spring is tricky to remove and even tricker to get back on so be warned.

Nikon 135mm f3.5 Lens - The helicoil key

To release the helicoils you need to remove the helicoil key. This is secured by two screws. These are often thread-locked so you will need to use some heat or Isoprop. The key itself is plastic so be careful with heat and avoid Acetone.

Make a note of the helicoil key orientation they are sometimes different. The 135mm is opposite to the 35mm in one of the other guides.

Nikon 135mm f3.5 Lens - Removing the outer helicoil

With the helicoil key out the outer helicoil can now be slowly turned out of the lens body.

The helicoil key can be recovered once you have some space with the helicoils wound out.

It is absolutely critical you mark the separation point so you can find the correct thread entry point later.

Nikon 135mm f3.5 Lens - Removing the inner helicoil

Now remove the inner helicoil and make sure you mark the separation point. In some ways on this lens it was easier to know the thread entry point.

With the correct thread entry point the lens stop block would meet the stop screw at infinity if the thread entry point was correct but its always wiser to mark the helicoils.

Inside the lens body you will see the two aperture control forks. The one with the larger gap is the stop down lever, the one with the smaller gap is the aperture control lever.
The aperture control lever has a small tab on its base with a slot for the screw you removed from the aperture ring earlier. Examine the aperture control fork and note its relationship to the slot on the lens body.

Make a note or mark up where the aperture control ring and fork are and then this can be unscrewed from inside the lens.

This is tricky to replace but on this lens the dried grease inside left no choice but to remove it for cleaning.

Nikkor-Q 135mm f3.5 NAI Lens – Cleaning

The Nikkor-Q 135mm f3.5 Non-AI lens stripped down for servicing

With the lens mechanics disassembled its time to clean all of the barrel parts. For this lens the optics were as clean as they could be so there was little point disassembling the optics. Richard Haws has a guide if you want to go that far into the lens. Generally unless you have fungus or issues to deal with its best to leave sealed optical assemblies alone.

For cleaning you will need a soft toothbrush, cotton wool balls and Isopropyl Alcohol (IPA) and a lot of patience. I generally clean down with hot soapy water first and then soak the helicoils in IPA for a few hours before wiping down with cotton wool. The threads on the helicoils are extremely fine and the smallest piece of grit or dried grease will cause problems later on. Usually the threads are chased out with a fine needle and/or a cocktail stick before cleaning again.

The aperture stop down ring in this lens is semi sealed into the lens body. There is no real reason to remove it. It contains a great many ball bearings and is awkward to get out. To clean the grease out I simply immersed the whole body unit in hot soapy water, scrubbed out the threads for the inner aperture control ring and then flushed the whole assembly with clean water and then used a hairdryer to dry it. The threads for the aperture control ring, filter ring and aperture ring were brushed clean with isoprop, a soft toothbrush and cotton wool until no old grease was seen.

All threaded parts were similarly cleaned and the silver anodised rings cleaned with some ‘Bar Keepers Friend’ which is excellent for removing small scratches, staines etc but be careful on painted surfaces it is quite acidic and somewhat abrasive. The dirty lettering was cleaned with a soft toothbrush and toothpaste to get the lettering nice and bright.

My own view on cleaning is to get the parts absolutely spotless prior to reassembly to give the lens the longest life before any further servicing is needed.

Normally when I rebuild a lens I will strip and clean EVERYTHING – it makes sense to get everything as perfect as possible to avoid future issues.

General note on lubrication: Normally on lenses I use Helimax XP as a general purpose helicoil grease. Helimax XP is readily available and works well for most lenses. On this lens though I am using Polar Bear BC-13A which is a substitute for Nikons own grease which is no longer available. Getting the dosing right for lenses is often hit and miss so you are advised to get a feel as you re-assemble the lens at each step. To get a feel you really need the focus barrel back in place and this can be readily refitted when the helicoils are assembled to check for feel. Too much grease will make the lens focus throw very stiff. Too little with make the lens focus throw feel too light.

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Aperture Ring Assembly

Nikkor-Q lubricating the aperture control ring

The inner aperture ring is given a light lubrication using Polar Bear Camera Grease Type BC-13A.

Lubrication needs to be very light here.

Note the small tab on the ring with the slot in it. The slot is for the outer aperture control ring screw.

Nikkor 135mm f3.5 - Replacing the inner aperture control ring

And now the internal aperture control ring is replaced. Positioning of this ring is critical and the following images will show you how this needs to be aligned.

This can be tricky to get back in place but its easier with the small spring removed from the stop down lever. Be careful not to cross thread this – the threads are very fine.

Aligning the inner aperture control ring

The inner aperture control ring needs to be aligned such that the slot on the small tab comes into view through the slot in the lens body. This is what the outer aperture control ring screw fits into.

Centre the slot in the aperture ring as shown.

Make a note of where the forks of the aperture control ring are located inside the barrel.

Lightly grease the aperture ring threads on the lens body using the BC-13A grease. And apply a light dose also to the aperture ring threads.

The small metal tab that provides the aperture click stops can be slightly bent upwards to provide a firmer click to the aperture ring if need be.

The aperture ring can now be threaded back on to the lens body. You will need to press the smal metal tab down a little to get the aperture ring on.

It’s easiest to start the thread with the aperture ring detents opposite the the metal tab – otherwise the sprung tab will interfere with finding the thread entry points for the aperture ring.

Screw the aperture ring down to the scribe mark you made during the strip down. This will position the aperture ring to its original position.

You can see the scribe mark on the lens barrel in the picture.

With the aperture ring in place its quite impossible to see the slot on the inner aperture ring tab. If you marked this up earlier is should align roughly to the middle f stop but I have found the orientation can shift slightly.
I use a thin probe to feel for the slot on the inner tab in order to orientate the aperture ring screw position.

Once the slot on the inner aperture ring is located correctly replace the aperture ring screw and then test that all is well by moving the aperture ring back and forth and checking that the inner aperture ring is moving correctly both backwards and forwards.

Once you are happy remove the screw and replace with a small dab of thread-lock.

Replace the stop down lever spring. This can be very awkward to exercise patience here.

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Focus Helicoils

Apply BC-13A grease to the inner helicoil and also to the outer helicoils inner threads, Wipe off any excess.

Using the thread entry point marks you made when removing the inner helicoil replace the inner helicoil into the outer helicoil. You can be sure that the inner helicoil is correct when the inner helicoil is blocked by the stop block (see next picture) with the two marks for infinity on the inner and outer helicoil aligned.

You can see in the picture the infinity mark for both helicoils is aligned.

The inner helicoil will be correct when the stop block on the helicoil is blocked by the set screw on the outer helicoil.

The inner helicoil will only fit on one thread entry point where this is possible.

Apply BC-13A grease to the outer helicoil and also with its recieving thread on the lens body.

The inner helicoil is now replaced using the same approach as the outer helicoil – eg using the thread entry point marks and a mark to indicate infinity. These dont show well in this picture.

You can see here that the outer helicoil, using the prevuiously marked thread entry point is back to its infinity marks.

On this lens it will be obvious if it is correct. If the wrong thread entry points have been selected the gap between the outer helicoil and the body will be either too large or impossible to achieve

Now unwind the helicoils enough so that you can insert the helicol locking key.

So long as both helicoils are aligned for their respective infinity points you cannot misalign them one to the other.

Insert the helicoil locking key.

Be careful of its orientation. On this lens the ledge is towards the back of the lens.

With the key inserted wind both helicoils back to their infinity position which will trap the key in place.

If all is aligned correctly at infinity the fixing holes for the key will be perfectly positioned.

Fix the locking key in place using the two screws. Be careful not to over-tighten. The inner helicoil threads are in quite a soft alloy which can strip easily if too much force is applied.

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Lens Sleeve

Replace the sleeve onto the lens body making sure it aligns with the aperture ring f stop markings.

Fix the sleeve in position with the three small screws around it. I usually use a medium strength thread-lock for these.

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Optical/Diaphragm Assembly

Looking down the lens you will observe the two aperture control forks. The stop down fork has a wide slot. The aperture ring fork has a narrow slot…

The optical assembly has a small screw which must locate between the narrow slot of the aperture ring fork.

The optical assembly aperture stop down control

The tab on the opposite side of the optical assembly must locate into the stop down fork slot.

Replace the optical unit in the lens body

Looking from the back of the lens will help you locate the positioning to ensure both of the aperture control levers are correctly aligned but it still relies on a fair amount of ‘poke and hope’ as visibility is not great. You should be able to feel for when the optical assembly is correctly located though.

Once the aperture control forks are correct you may need to twist the optical unit slightly to get its locating lug to fit into the slot on the inner helicoil.

With the optical unit in place you need to fix the filter ring in position. It’s the filter ring which retains the optical assembly and its threaded into the inner helicoil.

You need to tighten the filter ring down until the small holes for the grub screw aligns with the indent on the inner helicoil. This may be quite a tight fit

Replace the small grub screw with a dab of thread-lock.

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Focus Ring and Lens Mount

Nikkor-Q - 135mm f3.5 Lens Removing the focus barrel

Align the infinity point on the focus barrel and replace the barrel into the lens. Locate the three screw-holes and replace the three small fixing screws.

I normally only apply a single screw until I am happy the lens is working as expected. Once happy replace all screws with a small dab of thread-lock.

Replace the lens mount and its screws.

Mount the lens on a camera and check the infinity focus is correct and that the aperture control and stop down function as expected.

Check all external screws are replaced and use a small dab of thread-lock on each screw before refitting.

Nikkor-Q 135mm f3.5 NAI Lens – Outcome

Nikkor-Q 135mm f3.5 NAI Lens after rebuild.

After rebuilding the lens operated perfectly well. The aperture click was somewhat softer than I had hoped. I generally prefer a very ‘clicky’ feel but many older Nikon lenses do suffer a softer than normal click due to wear. The lens is perfectly usable and now able to return to actual use with me for use on my own Nikon F.

This particular version of the lens is well regarded by Nikon users despite its relatively humble specification and I will be looking forward to using it in the near future.

I hope you will find this article of use in your own lens repair and servicing.

While waiting for Isoprop to release the nasty Nikon threadlock why not have a read of our review of the Nikon F

Mel

Mel is one of the driving forces behind High 5 Cameras and writes all our articles.

www.high5cameras.com

Posted on June 6, 2025July 8, 2026 by Mel — Leave a comment

Repair Nikkor-S 35mm f2.8 Non AI Lens

Repair Nikkor-S 35mm :- A short guide to servicing the Nikkor-S 35mm f2.8 Lens.

Nikon has been making the 35mm f2.8 lens since around 1959. The first version was around from 1959 to 1962 and was called the Nikkor-S. The original lens had 7 elements in 5 groups and is easily recognised as its focal length on the beauty ring is in cm rather than mm and reads 3.5cm. The mount type is Nikon F Non-AI.

The slightly revised version from 1962 to 1974 has 7 elements in 6 groups and is easily identified by its focal length being in mm as shown on its beauty ring. Mount types for these are Nikon F and non-AI but some versions would have been converted to AI either by the factory or aftermarket technicians.

Nikon produced many different versions of this lens but across its lifespan there are only 4 optical variations. This guide covers the 1962-1974 versions but the earlier version will be nearly identical. This particular lens bears the Nippon Kogaku name rather than Nikons and thats a reasonable indication that the lens is a very early version and probably dates from 1962-1964. Nikon dropped the Nippon Kogaku name around 1966 although some lenses still bore the NK markings until the 1970s. This lens proved out to be somewhat different to the lens shown in Richard Haws guide to this model of lens.

It should be noted that Nikon struggled with 35mm SLR lenses in the early period and lenses from this era can show a lot of internal messing about with additional holes, slots and scriber markings all done by the factory as Nikon tried to get to grips with the design and production.

The lens was acquired in very poor condition and had a very loose focus due to the focus helicoils having dried and vaporised grease but a very tight aperture control ring due to old grease going solid.

NOTES:- REPAIR NIKKOR-S 35mm f2.8
The Nikkor-S 35mm is a relatively easy lens to work on for the most part but like many vintage lenses it has its foibles. It is absolutely critical with this lens that you mark the helicoils for infinity focus and separation points. Failure to do so will result in a lot of issues during reassembly.

The internal construction is very solid but it does have its oddities compared to some other manufacturers. Some of this no doubt as result of Nikon struggling with the demands of early 35mm SLR cameras.

You will absolutely need a good set of screwdrivers for this lens that are correctly sized. Attempting this repair with amateur tools will result in problems. I would recommend the pro-set of screw drivers from Polar Bear Camera together with the special Nikon driver for removing Nikon slotted screws on the lens mount if the lens has slotted screws.

Screws on Nikon lenses are typically hard to deal with, Nikon used a lot of thread lock and lacquer on the screws. You will need Isoprop and Acetone to remove these or use the tip of a soldering iron to head the screw head which will weaken the thread lock.

Bear in mind also that this lens is composed of a lot of quite soft alloys. When refitting screws apply no more force than you can exert between thumb and forefinger on the screwdriver and replace using thread-lock. Right let’s repair Nikkor-S 35mm lenses.

Nikkor-S 35mm NAI Lens – Stripping Down

Set the lens to infinity. As you work on the lens at the initial stages make sure that the infinity position is retained. Like many old lenses you will most likely find the lens comes to infinity just at the start of the infinity mark and focuses slightly past infinity.

This is quite common – the manufacturers built in an allowance for glass expansion.

Nikkor-S 35mm lens repair - the focus barrel

The focus barrel will now pull free from the lens. It may need a little twist to remove it. This particular lens had hardened dried grease behind the focus barrel making it harder than expected to extract.

If you twist it try to reestablish where infinity focus was by aligning the screw holes in the focus barrel with the main body of the lens.

Nikkor-S 35mm lens repair - the front optic

Use a lens spanner to remove the front optical unit. This will have slots to extract this.

Here is the front optical group removed from the lens.

Nikkor-S 35mm lens repair - the front barrel

Remove this set-screw from the front barrel/filter ring.

The front barrel unscrews from the lens. This is one of the unusual features of this lens. Almost all parts are screwed together rather than simple press fit with retaining screws.

Make a note as you unscrew the barrel that there will be a dimple which the set-screw was located to.

The front barrel/filter ring has now been removed. You can see the location of the small dimple as indicated where the front barrel set screw located.

Nikkor-S 35mm lens repair - removing the mount plate

Remove the screws at the rear of the lens thats secure the mount plate. These are almost always hard to extract. Nikon will have used a lot of thread-lock here but you can use acetone CAREFULLY or the top if a soldering iron on these screws. A correctly sized screwdriver is essential here – we strongly recommend the specialised driver tip sold by Polar Bear Cameras to avoid chewing the screw heads up.

As the mount plate comes away take note of the forks on the rear of the mount plate and how they locate to the small tab on the lens diaphragm assembly.

There is no value in disassembling the mount assembly. If you are forced to do it for any reason beware – there are an awful lot of ball bearings which provide the aperture stop down mechanism with a frictionless feel.

Nikkor 35mm f2.8 - Removing the lens core

Depending on the lens there may be screws retaining the core of the lens comprising the diaphragm and rear group assembly. It is possible these are absent. Older Nikon lenses are quite often slightly different internally and often show signs of extra drilling or cutting done by the factory.

If screws are present to retain the lens core assembly remove them.

This lens lacked the retaining screws and instead simply had a locating screw that aligned with a slot. The lens core can simple be pulled free.

The whole assembly is simply held in place by the front optical unit on this lens.

Here is the core part of the lens removed. It shows no grub screw fixing points so I imagine the factory had simply not fitted them for some reason.

The core part contains the diaphragm assembly and the rear optical group.

Nikkor 35mm f2.8 - Removing the barrel trim

Measure the gap between the index barrel and the aperture control ring. I normally use the tip of a screwdriver to gauge the distance and make a note.

Remove this screw from the index barrel and remove.

The index barrel will simply pull free from the lens body. It may be a bit stiff due to dirt being trapped underneath.

Scribe a small mark as to where the aperture ring is fitted. This will be useful later to establish its position.

Nikkor S 35mm - removing the aperture ring

Remove this screw from the aperture ring. This screw locates to the aperture ring inside the lens which controls the aperture. You will see this in the next few steps.

The aperture ring unscrews from the lens body, unlike many lenses it does not simply pull free. You may find it is very stiff in its threads.

With the lens still at infinity from the start of the work. The inner helicoil is scribed along the stop plate to indicate its infinity position – the red dotted line indicates where to mark as the scribe mark doesn’t show well on a photograph.
Also create a mark on both the inner and helicoil to show where infinity was reached.

Marking the infinity position is really critical.

Nikkor-S 35mm f2.8 NAI -measuring the helicoil gaps

With the inner helicoil marked the outer helicoil position has to be checked. You can do this by marking the barrel and the inner helicoil with a mark indicating infinity. Also measure the gap between the outer helicoil and the lens body.

NOTE THE ORIENTATION OF THE HELICOIL KEY

With the focusing helicoils marked up and measured its time to remove them from the lens. You will need to remove the two screws that retain the helicoil key.

These can be very tough to extract and usually you will need to be able to apply some heat using the tip of a soldering iron. You need to be careful as the key itself is sometimes plastic.

With the helicoil key retaining screws removed wind the lens focus out using the outer helicoil and extract the key from inside the lens body.

With the helicoil key removed simply unscrew the outer helicoil but make sure you mark the point at which the helicoil separates.
I usually mark each helicoil with a > and < to indicate the point at which the thread separated. It’s essential with this lens to get the right thread entry points to avoid headaches during rebuild.

Nikkor 35mm f2.8 NAI focus helicoil seperation

With the outer helicoil out of the body remove the stop plate on top of the outer helicoil.

With the stop plate removed the inner helicoil can be unscrewed. Once again make sure you mark the helicoils with the separation point.

Nikkor 35mm f2.8 NAI aperture inner ring removal

The internal aperture control actuator is retained by a thread.

Mark the internal aperture ring position inside the lens body

This ring can now be unscrewed and its threads cleaned.

Nikkor 35mm f2.8 NAI aperture inner ring

Heres the aperture control actuator now removed from the lens body.

Repair Nikkor-S 35mm f2.8 NAI Lens – Cleaning

Nikkor-S 35mm f2.8 NAI Lens disassembled

With the lens disassembled it’s time to clean all of the barrel parts. For this lens the optics were as clean as they could be so there was little point disassembling the optics. Richard Haws has a guide if you want to go that far into the lens. Generally unless you have fungus to deal with its best to leave sealed optical assemblies alone.

For cleaning you will need a soft toothbrush, cotton wool balls and Isopropyl Alcohol (IPA) and a lot of patience. I generally clean down with hot soapy water first and then soak the helicoils in IPA for a few hours before wiping down with cotton wool. The threads on the helicoils are extremely fine and the smallest piece of grit or dried grease will cause problems later on. Usually these are chased out with a fine needle and/or a cocktail stick before cleaning again.

My own view on cleaning is to get the parts absolutely spotless prior to reassembly to give the lens the longest life before any further servicing is needed.

Normally when I rebuild a lens I will strip and clean EVERYTHING. The lens mount assembly can be flushed with IPA, all of the barrel components such as the aperture control ring, filter ring and focus barrel will be thoroughly cleaned. Index marks with their numbers can be scrubbed with a soft toothbrush to remove dirt and grime.

General note on lubrication: Normally on lenses I use Helimax XP as a general purpose helicoil grease. Helimax XP is readily available and works well for most lenses. On this lens though I am using Polar Bear BC-13A which is a substitute for Nikons own grease which is no longer available. Getting the dosing right for lenses is often hit and miss so you are advised to get a feel as you re-assemble the lens at each step. To get a feel you really need the focus barrel back in place and this can be readily refitted when the helicoils are assembled to check for feel. Too much grease will make the lens focus throw very stiff. Too little with make the lens focus throw feel too light.

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Aperture Ring Assembly

Nikkor S 35mm lens service - replacing the internal aperture ring

The inner aperture ring is given a light lubrication using Polar Bear Camera Grease (Type BC-13A).

Lubrication needs to be very light here.

Nikkor S 35mm Servicing - the internal aperture ring

And now the internal aperture control ring is replaced. Positioning of this ring is critical and the following images will show you how this needs to be aligned.

Apply a light coat of lubricant (this is the same BC-13A lubricant) to the aperture ring threads. Note the small metal tab which provides the click stops for the aperture ring. If the aperture stops are not ‘clicky’ enough you can gently bend the tab out slightly to give a more positive click.

Nikkor S 35mm repair - the aperture ring

Replace the aperture ring after giving the rings threads and detents for the click stops a light dose of lubrication using the BC-13A grease.

This screws on and may be very tight at the start of the thread as the tab which provides the click stops may be pressing against it.

Here the silver barrel ring with the index scale has been applied so that the gap between the aperture ring and the barrel index can be checked and adjusted if need be.

The aperture ring needs to align well with the index ring barrel without too much gap but it also needs to align with the inner ring which will be next to check.

The aperture ring needs to align so that the small screw on the outside of the aperture ring fits between the slot in the body and the small slot on the internal aperture ring.

I use a cocktail stick to get alignment correct.

Replace the screw in the aperture ring. Do not tighten this down just yet. You may need to make changes.

Once you are happy you can tighten but be careful – the threads in the aperture ring are very fine and the ring is a light alloy – you can strip threads easily here so go careful. At the end of the process return and apply some thread-lock to this screw.

With the aperture ring assembly done check that the ring moves easily with the required click as it runs through its stops.

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Focus Helicoils

Replace the helicoil key into position making sure it is orientated correctly.

Nikkor-S 35mm - Outer helicoil lubrication

The outer helicoil is now lubricated using a sable brush to apply some lubricant. For this lens I am using the same BC-13A lubricant which will give a very light feel. If you prefer a stiffer feel then Helimax XP is a suitable alternative.

You should add a very thin layer of grease to the receiving threads on the lens body as well. Wipe off any excess.

The outer helicoil is now replaced. You can see in his picture the thread entry point markings of > and < together with the line which indicates infinity focus position. The gap between the helicoil and the lens body is also checked to confirm positioning is correct.

The inner helicoil is now lubricated using the same BC-13A grease as before. Dont over apply the grease as it will cause the focus to be excessively stiff. Getting the ‘feel’ right can take a bit of time but comes with practice.

Add some grease to the receiving threads in the outer helicoil and wipe off any excess

The inner helicoil is now replaced using the same approach as the outer helicoil – eg using the thread entry point marks and a mark to indicate infinity. These don’t show well in photographs. The scribe mark along the stop plate is checked to confirm positioning.

The helicoil key retaining screws are now replaced. If all of the alignments are correct with respect to the helicoils the screw holes for the key will be in a perfect position.

Replace the stop block onto the outer helicoil. Be careful it has a top and bottom side. The top side has a rebate to allow the screws to be flush.

As a note this is good practice for tightening screws inside lenses. You need no more force than you can apply using thumb and forefinger – this will avoid stripped screws threads which are often in thin and light alloys.

Now you can repair Nikkor-s 35mm lenses it’s time to start remounting the optical parts – Before you do you should quickly test the focus throw by turning the outer helicoil.

If all is correct the lens helicoils will move smoothly and will impact the stop block at infinity AND at minimum focus distance.

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Rear Optical Assembly

Inserting the diaphragm and rear optical unit

Insert the diaphragm and rear optical element core part of the lens – note that the screw at the base of the diaphragm unit must engage with the forks of the inner aperture control ring – see below.

Engaging the lens core with the aperture control forks

You can see in this picture that the small screw on the rear of the diaphragm assembly has located correctly between the forks of the inner aperture control ring.

The screw has located correctly into the aperture control forks but the screw to the top is out of line – thats not an issue – simply rotate the lens core with the diaphragm until it aligns and then push down – see below.

The diaphragm and lens core are now seated correctly.

If the core did have retaining screws (this one didn’t) replace them now.

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Lens Mount, Sleeve and Filter Ring

Replace the lens mount make sure the forks on the lens mount locate over the small tab on the rear of the diaphragm.

A handy tip here is to set the aperture ring to f16 and then rotate the lens mount around, watch the diaphragm as you rotate the lens mount. At the correct position the diaphragm will close to f16 and the screw holes will be correctly located.

Replace the screws but do not over-tighten in case you need to re-do the lens.

Replace the index sleeve and secure with the three small screws. You will need to locate the holes in the lens body.

Normally I only apply a single screw until I am happy that the lens is fully working after a test.

Nikkor S 35mm replacing the filter ring and front barrel

Replace the filter ring barrel, this screws on. Screw it down until the screw-hole is positioned above the small dimple in the inner helicoil.

Replace the small setscrew.

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Front Optical Assembly and Focus Barrel

Replace the front optical unit…

…and tighten down with a lens spanner.

On this lens the only thing holding the entire optical and diaphragm assembly in place is the front optical block. Ensure this is suitably secure but do not over-tighten.

The Nikkor-S 35mm f2.8 lens after servicing

With the lens fully rebuilt check that infinity focus is correct, that the focus throw runs from infinity to minimum distance smoothly and that the aperture control and stop down are all working correctly.

Once you are happy replace any screws – if like me you left a few out pending testing – and then tighten all screws using a small dab of thread-lock .

Nikkor-S 35mm f2.8 NAI Lens – Outcome

After rebuilding the lens and it operated perfectly well. There was a small issue which showed up in the focus throw. This was being caused by the front filter ring being slightly distorted. I suspected a drop at some point in the past. A small amount of pressing out the ring to a more perfect shape resolved this issue.

This version Nikkor-S 35mm f2.8 is quite an old unit as attested to by the Nippon Kogaku name on the front of the lens and as a result its coatings are primitive compared to a modern lens, or even a later Nikon. For shooting with, it will need to be carefully handled and used with a lens hood to avoid ghosting and flare.

I hope you will find this article of use in your own lens repair and servicing. While you are waiting for Isoprop to release the nasty Nikon threadlock why not have a read of our review of the Nikon F

Nikon FTn Finder – Servicing & Foam Removal

The Nikon FTn finder in common with a lot of cameras from the golden age of film cameras contains a fair amount of foam. Like the Olympus OM-1, the Canon FTb and many others the foam around the prism slowly degrades. When it does the foam turns into a toxic goop that will de-silver the prism and ruin it. While other cameras have the same issue the Nikon FtN finder is complicated by the fact that the prism itself is quite a complex piece and spares are hard to find.

In this easy, step by step guide, I’ll show you how to take the FTn finder to pieces and avert disaster with your Nikon – left to itself the internal foam WILL eventually destroy your prism.

Notes on working on the FTn Finder
As ever Nikon have a love affair with thread-lock. You may come across screws that wont shift. As ever a dose of Isoprop will usually get them moving but you also need correctly sized screwdrivers. Be careful of using Acetone during any disassembly work, remember there are optical parts inside that can be damaged easily.

The work is not hard but as ever with any finely engineered optical system you need extreme care. Take your time and exercise patience and care. The parts inside the FTn finder are almost irreplaceable so its as well not to rush in and wreck things.

Nikon FTn Finder – Stripping Down

Remove the leatherette from the Nikon FtN Finder

Make sure when the finder is off the camera the prism face on its base is kept safe. I normally use a soft lint free cloth underneath.

Apply some Isoprop to the edges of the leatherette to weaken the glue, you may need several doses. The leatherette can then be lifted at an edge using a fine scalpel and then slowly pulled back. Be careful not to tear it.

Below the leatherette you will find 4x screws that retain the FTn finder top cover. Remove these and slip the top cover away.

With the top cover removed you will see the variable resistors which trim the battery check and the meter functions.

Note the round cut-out to the side with the wires.

Note: this pic was taken during rebuild and tuning but it will look the same.

Slacken the screws on the finder and release the wires

Slacken the screws that retain the wires, do not remove the screws just loosen them enough to release the wires. Note that the left most screw retains a copper strip, slacken this screw as well and very carefully free the copper strip.

It’s not possible to separate the two halves of the FTn finder until these wires and the copper strip are released.

Remove the face plate screws from the finder.

Be careful as you remove the front plate from the finder not to damage the aperture tab. You may need a little bit of wriggle to free it.

The aperture mechanism on the FtN finder

With the front plate removed you can examine the aperture sensing mechanism of the FTn finder. Be careful not to disturb the small spring.

Often these are caked in grease and dirt. Use a soft brush lightly moistened with Isoprop to clean any debris away.

Turn the finder over and remove the four screws indicated.

Note that the screws at the rear of the finder are a different size to those at the front. The rear screws are slightly smaller in width.

With the screws removed the finder can be separated. Take care that the wires do not snag as you separate the two halves.

The top half contains the mechanics while the lower half contains the prism and electronics.

With the two halves of the finder separated watch out for 4x small washers located at the corners of the lower half. These are usually stuck down and will stay secure but you should be aware of them.

Note: This picture was taken during a later stage of the strip down as the original picture was not good.

Remove the prism retainer tab screw indicated and remove the retainer.

De-solder the brown wire running from the battery case to the circuit board.

Be very careful handling this circuit board. It’s an old school mica board and will crack very easily under any stress.

Remove the screw that retains the sprung metal part which retains the meter cells

Remove the screw indicated that retains the sprung metal part which retains the meter cells and extract the retainer.

Remove the circuit board retaining screw. This is the screw that was holding the copper strip when the wires were released earlier.

It was not removed earlier in case it slipped down inside the finder. Its far safer to remove now.

Removing the circuit board from the FtN finder

The circuit board can now be removed, exercise extreme care.

It is easiest to remove it by gently lifting the meter cells upwards out of their holders.

Watch out for small ND filters immediately under this board. These were used by the factory to balance the meter cells. Make a note of which side they come from as they are often different values.

Remove the second prism retainer screw and extract the retainer.

In this picture you can see the locations of where the ND filters were positioned – the two circular cut outs. None were present on this finder but they are often present and were used to balance the meter cells.

Remove the two screws indicated. These retain the meter cell platform. Once removed pull the platform free and remove it.

You will now be getting your first look at the state of the foam beneath.

The prism itself can now be carefully lifted out of the finder base.

Note that the prism contains various reflectors for the meter and shutter speed read-outs and also has two small prisms glued to its back for the meter cells. Be careful using chemicals around these as the balsam used to cement them may fail if exposed to chemicals like Isoprop.

Nikon FTn Finder – Cleaning and Foam Replacement

With the FTn finder stripped is now time to get to work cleaning and removing old foam. All of the external metal work is cleaned up and the interior blown clean of any old foam fragments which, in this one, had migrated everywhere. Check all parts carefully.

You can see in this finder the foam was in a very poor state. The prism needed serious attention as it was an ace away from the foam eating the silvering. Extreme care is needed as foam breakdown can affect the stability of the external paint on the prism.

Clean the prism carefully with a small amount of Isoprop just dabbed on to the old foam. Give the Isoprop 10-15 minutes and then gently wipe. Be very careful – on this prism the foam had started to degrade the external black paint. Go slowly and carefully.

The meter cell platform can be cleaned with Isoprop but keep chemicals away from the small lenses for the meter cells.

These foam pads around the viewfinder area had also badly disintegrated so needed to be cleaned off. Some Isoprop removed them easily.

To get the right width of the replacement pads I have replaced the meter cell platform and am adding a slight score line so I know where the pads are supposed to end.

Fresh 1.5mm thick foam pads have now been added. These are cut from Japan Hobby Tools stock open cell 1.5mm foam.

The meter cell platform is given a strip of 1.5mm open cell foam. Getting it to run correctly with the twists and turns was a challenge.

I wanted to use felt but the felt stock I had was just not thick enough or compress-able enough when layered. This foam will last another 15-20 years!

Clean the small reflector mirror if needed. DO NOT USE CHEMICALS – like the main mirror this is a front silvered mirror. Use just breath and a gentle wipe with a cotton bud.

The top half of the finder contains the mechanics but also the carbon track which provides the variable resistance for the meter. These are a known source of trouble for the Nikon FtN meter head as the tracks can be worn away and there are no replacements.

Take note of the small brushes with the red dab of paint on them and avoid cleaning anywhere near these. They are very fragile.

The carbon track can be cleaned gently with a cotton bud and dilute Isoprop to remove dirt from the track. Go carefully here, the track can easily be damaged.

To avoid the very fine brushes turning the shutter speed control on the finder will cause the track to move backwards and forwards to allow access to each part of it.

Nikon FTn Finder – Assembly

During disassembly the eyepiece surround can fall out. Replace this in position and make sure it stays in place.

Clean all prism surfaces and replace the prism back into the lower half of the finder. Avoid chemicals especially around the joins for the meter and speed reflectors and the rear mirror for the meter cells.

Make sure it is seated correctly as it has a tendency to get caught and jam on its front against the finder lower part.

Replace the left side prism retainer and its screw. This needs to be held firmly against the prism but not so much pressure you risk damaging the prism.

Replace the meter cell platform using the 2x screws.

Don’t forget to replace the ND filter(s) in their original positions if they were present during strip down.

Replace the circuit board into position, make sure the meter cells locate correctly into their fixing points and then apply the retaining screw – dont tighten the screw – you will need to release it later.

Replace the sprung meter cell retaining part and refit the screw.

Solder the brown wire from the battery case to the circuit board.

Refit the right side prism retainer.

Replace the base to the top of the FtN finder

Replace the base of the finder onto the top half.

Replace the 4x screws – remember the smaller screws go to the rear, larger screws to the front.

Check and replace if necessary the foam pads either side of the viewfinder on the base of the finder.

These are often ok as they are easy to change and sloppy repair techs may change these even when they wont have stripped the finder to get at the foam inside.

These can be removed using a dab of Isoprop and replaced if necessary with 1.5mm open cell foam.

Fresh pads added here. Check the raised part as well for old foam contamination, the camera body has a foam pad which butts up here. Check that this is clean and has no glue residue. If it does make sure to replace the pad on the camera body.

Check the mechanics at the front of the finder are clean and apply a very thin smear of lithium grease to the slide slots as shown. This needs to be no more than a very thin film of grease.

Replace the front plate making sure that the slot for the aperture lever goes over the lever and does not foul on the lever.

Reconnect the wires and the copper strip to their terminals and tighten down. These dont have to be much more than hand tight.
REMEMBER the circuit board is very fragile.

Replace the finder on the camera for setting up the meter.

NOTE: You can be easily thrown here and think the finder is not mounted properly – this is because you are used to seeing the side of the finder fit flat to the camera body. With the top cover removed there is a sizeable gap between the sides of the finder and the camera body.

Nikon have a typically awkward set-up procedure in their service manual for adjustment and few people will have access to a calibrated light source. Generally you will need to compare the meter with a known good camera.

Unless these have been messed about with they will most likely be correct and are best left alone.

See the section at the end for calibration settings.

Replace the top cover and secure with the 4x screws.

Replace the leatherette using a good quality gum rubber or contact cement. Pliobond is the best for this kind of work.

Nikon FTn Finder – Calibration

Nikon advise a rather complicated method for calibrating the meter. In part this is driven by having to set the resistance for each of the CdS cells using an external resistor to balance the cells. While this procedure is useful should you change cells it’s of little value in simply determining the meters readings and adjusting for known light values.
A full technical description is given the Nikon FTn service guide which is available at learncamerarepair.com a simplified approach is given below based on light value.

The examples given are from a known good FtN finder using a 50mm f1.4 lens set at its mid point between f5.6 and f8.

Set the finders film speed at 100 ASA .

Using a calibrated light source the meter needle should centre at the following settings.

BATTERY CHECK – Assuming fresh batteries should be as shown in the picture with the needle to the left of the centre point. When the battery check moves the needle to the right of the centre the battery is exhausted.

Calibrated Source at EV14 – Shutter Speed 500th

Calibrated Source at EV11 – Shutter Speed 1/60th

Calibrated Source at EV8 – Shutter Speed 1/8th

The settings above were done using 2x SR44 1.5v batteries as I wanted the meter calibrated for 1.5v. I suspect the meter when new would have centred the needle at f5.6 exactly which would be the correct speed and aperture for the EV and would accord with other manufacturers specifications. However, I believe the meter cells have weakened somewhat and a small error was introduced by the use of 1.5v batteries rather than Zinc Air batteries of 1.35 volt which would be closer to the original battery specified using mercury cells.
The setting above have been used with live film and the meter was found to give perfect exposures.

If you do not have access to a calibrated light source your only option is to check the meter against a a known good camera over a range of lighting conditions. Most guides will tell you to use a grey card that is 18% percent off-white. I find that sort of advise not useful to most people who lack the facilities for a reliable off-white card and stable light conditions.

The best assessment is to compare with a known good camera using a similar lens and assess the camera over a range of lighting conditions and scenes. Don’t’t forget different manufacturers used different metering patterns but, so long as the scenes you assess are identical for each camera then you should be able to get close enough. If you find the meter is causing you to underexpose or overexpose then you can adjust later if need be.

Brief History of the Nikon FTn Finder

The Photomic FTN finder was the last finder developed for the Nikon F and launched in 1968. The FTn is considered the best finder for the iconic Nikon F body for it’s better handling and its ability to ‘automatically’ manage adjusting for the lens aperture range, albeit this was a bit of a fuss compared to Minolta. Minolta lenses automatically couple to the meter as soon as the lens is mounted where Nikon required the Nikon ‘Twist’ – Mount the lens then rotate the aperture ring from maximum to minimum to couple the meter.

The metering pattern was the same as the previous TN finder with a 60/40 centre weighted pattern which Nikon continued to use throughout most of their film cameras.

The FTn started shipping at F body serial number 690000 and continued until the end of F production in 1974.

The FTn was the first and last F Photomic to have shutter speeds visible in finder. More securely attached to the camera body than its predecessors, the FTN used a new front latch over the nameplate. It was released by a black plastic tipped lever on the finder’s left side, this was requested by users at the time as they felt the single latch at the rear was insufficient.

Bodies shipped after serial 690000 had a Nikon nameplate with square edges, the later FTn finder required a rounded off edge to allow it to fit. The nameplate is only secured by 2 screws so is easy to change if you can find one.

Nikon FTn advert 1969 — Nikon advert featuring the TN finder circa 1968 – when this advert launched the TN had already been replaced by the FTn!

Film Camera Service – A True Crime Story of What Lies Beneath

Film Camera Service – There exists within the classic film camera fraternity something of a mythology about Japanese cameras being ultra-reliable. They will ‘oohh’ and ‘aahh’ about how their 40-50 year old camera still works. The truth is they are often unaware that, while these things were made to a quality that no manufacturer outside of aerospace or military application would attempt today, they were made with the technology available at the time. Part of this technology included organic lubricants which tend to vaporize and dry out over time and worse they used foam, A LOT!

WARNING! This article is unsuitable for those inclined to suffer camera hypochondria by proxy or have a nervous disposition. Viewer discretion is advised.

Now most film camera folk will be aware that light-seals and mirror bumpers tend to degrade but are usually blissfully ignorant of the fact that very often these cameras contain a lot of foam and rubber seals internally which just like the light-seals decay – this is what lies beneath the skin of many classic cameras and it’s a real problem. The internal seals are often close to precision mechanics – as the inner seals decay they tend to scatter fragments of foam and general goop into mechanisms which should be clean, and indeed, must be clean for the camera to work properly.

Lets take a look at what lies beneath two popular cameras in two cases of real life camera crime.

Pentax ME Super – Femme Fatale

First up is what is probably the worst camera of the lot that I have dealt with which is the Pentax ME Super. Something of a femme fatale – the ME Super is claimed by Pentax fans to be much loved but like any film noir vamp the interior of the ME Super is usually corrupted. Pentax fans claim it’s love but to me it seems more like lust – as soon as issues appear they discard the camera – rather like the private eye will dump the bad girl/temptress in a classic noir movie.

The ME Super contains a lot of internal foam seals plus rubber parts which are almost always in a poor state. Some of these are responsible for the strange case of the endless wind on for the camera – and wind up for its owner.
When I say a lot of foam I mean it – around 18 foam seals not including the mirror bumper or light seals plus an additional six rubber parts which decay. Three of those rubber parts will eventually cause the camera to suffer the famous ‘double wind’ issue where the camera will wind on repeatedly without ever charging the shutter. Two will cause the camera shutter speeds to degrade and slow down and the final one, the air piston buffer, will generally not cause an issue which is of small consolation when the camera fails entirely due to the other five rubber parts failing.

Film Camera Service - Pentax ME Super Mirror Box Washers — The dreaded mirror box rubber washers – you can see the one to the far right is disintegrating. Trouble in store.

Film Camera Service - Pentax ME Super - Rubber stops degrading in the shutter mechanism. — The small rubber stops in the shutter – these degrade and slow the shutter down.

Film Camera Service - Pentax ME Super - Mirror Air Piston — The air piston for the mirror. This one has had a brand new washer fitted.

With the ME Super it’s not just the quantity of the seals it’s the size of the largest one and the proximity of many of these seals to the very sensitive shutter. The ME Super uses a vertical metal bladed shutter and like all vertical shutters it needs to be clean for fast operation. One bit of decayed light seal in the works can really mess things up but the real culprits will usually be the two rubber bumpers inside the shutter which almost always decay into glue. As if that’s not all bad enough the focus screen arrangement on an ME Super uses three seals, all of which are in close proximity to either the focus screen or the prism. Scattered pieces of foam on the top of the screen are impossible to remove without taking the prism out which is no easy job on the Pentax ME and one of the seals is in direct contact with the prism creating a risk of prism de-silvering.

Film Camera Service - Pentax ME Super internal foam block — The really large internal seal. This one was breaking down badly.

Film Camera Service - Pentax ME Super - Seal to the rear of the mirror box — Rear of the mirror box. The seal has almost entirely failed.

Film Camera Service - Pentax ME Super - Seal around focus screen carrier — The focus screen carrier seal busy scattering fragments while eating the brass carrier.

Film Camera Service - Pentax ME Super prism seal — The prism seal/bumper. Its just waiting to eat the prism silvering.

Film Camera Service - Pentax ME Super - seal material on edge of shutter mechanism — It’s not just the big seals – its the small ones too ! This is one of the shutter seals.

Film Camera Service - Pentax ME Super - Internal Seals — The seal over the LED array – spreading dirt onto the focus screen.

Like most cameras which make extensive use of foam the internal seals on the Pentax ME Super require a full on service to replace them which usually involves a near complete strip down of the camera to its major components. The pictures give you some idea what’s happening inside the average Pentax ME Super. The camera may work now but ultimately it will become another victim of foam decay crime. Pentax owners often tell you how much they love the ME Super – few of them seem to love it enough to want to spend money having it serviced or buying one thats had a complete rebuild.

Pentax ME Super undergoing servicing — Film Camera Service – One of our Pentax ME Supers starting its new life. Start of the strip down to get it ready for fresh foam and rubber seals, lubrication and finally testing and calibration to the manufacturers original specification.

Now, its fair to say that a full on service for the Pentax ME Super is never going to be cheap. At least in the mindset of most modern film users. To be fair I had one tell me recently he couldn’t afford to pay for a service manual costing around £3! Less than a cup of coffee. I’d suggest in his case he picks up a cheaper hobby. A full blown service for the Pentax ME is quite a bit of work but its still cheaper than a plumber charged me for fitting some new taps. As ever everyone has to come to their own conclusions about value. I can only show and tell you what’s inside one of these cameras and leave it to you to (hopefully) do the right thing and get it serviced. Pentax wont be making anymore of them anytime soon so it makes sense to preserve what’s left – buying another cheap one is just kicking the can down the road.

Minolta SRT – More sinned against then sinning

Minolta SRT-101 – Another villain for internal foam issues or more of a victim?

Now lets look a camera made a generation earlier than the ME Super and the camera closest to my heart, the Minolta SRT Series. The SRT in its earliest form used around 14 internal foam seals. As production progressed over the next decade and a half Minolta progressively removed foam seals and dampers from inside the camera. The very last production SRT-100X model reduced the count to around 6. While these seldom cause major problems other than crumbly seal material getting on the focus screen the fact that they are failing is usually a sure sign that the camera will be having issues with its shutter speeds.

If the foam is going bad (and it always is) you can bet the lubrication has long gone from the shutter rollers which the camera is dependent on for accurate shutter speeds. Like the Pentax ME Super the Minolta SRT series can be holding a lot of dark secrets inside. Unfortunately SRTs have a reputation for being unbreakable – users will claim the camera still runs perfectly. Experience servicing them tells a different story with shutter performance almost always seriously degraded due to lack of lubrication and dried out old foam getting into stuff. The SRT is less villain and more of a victim of foam ignored by the average user blissfully (or wilfully) ignorant of whats happening inside.

Film Camera Service - Minolta SRT101 - Base of the mirror box — The failing foam in almost all early SRTs. This is the base of the mirror box

Film Camera Service - Minolta SRT-101 Mirror box springs — Minolta removed the foam in the base but added it to the springs shifting the problems elsewhere!

The worst of the internal seals is the bottom seal of the mirror box, absent in later models, which, as it degrades starts to shed foam fragments into the lower curtain rollers. Later ones swapped this problem for a different issue, like all good detective novels there’s a plot twist. Minolta stopped adding this lower seal and replaced it on later models with foam inserts into the springs on the mirror box in a devious plan to change the issues from the curtains to the mirror mechanism. These can lead to the mirror box failing as fragments of old foam get jammed into the various lever pivots and gum the mirror box up. Thankfully SRTs never have degrading foam near the prism but they do use a foam block under the meter galvanometer which is usually responsible for foam being spread over the top of the focus screen.

Minolta SRT101 the secondary bumper — Replacing the mirror bumper is easy – but theres a second bumper which is not!

Minolta SRT101 - Top of the mirror box — Decaying foam seals at the top of the mirror box.

Minolta SRT-101 foam in the base — The spring damper – these can degrade badly and start corroding the spring in the base.

Minolta SRT101 door latch foam — Early SRTs have a foam pad by the door latch – this degrades and starts eating stuff like the meter trimmers.

Minolta SRT pad under galvanometer — The pad under the galvanometer – this is one thats been replaced along with the mirror box foams.

Minolta SRT seal under top cover — The one everyone forgets – the seal under the top cover.

Like the Pentax ME super the only way you can resolve the decaying foam is a complete strip down to the major parts. The secondary mirror bumper for example is almost impossible to resolve without removing the mirror box and removing the sprung light-shield. Shockingly lots of service places will do a halfway house job (on the SRT and a lot of other cameras too). They’ll tighten the shutter rollers and squirt some powdered graphite in to make the camera feel smoother but its not a good way to approach the SRT – or any camera for that matter.

Like the Pentax ME Super a full on service is likely to cost around £120 but done well the camera will perform beautifully and last a lifetime.

Minolta SRT during servicing — Film Camera Service – One of our SRTs during servicing. A complete strip down, cleaning and lubrication, replacement of all the old foams and finally calibrated to Minolta factory specification. The next best thing to a brand new camera!

Other cameras, other service issues…

I have only selected two cameras for this article but almost all cameras from this age will tend to have similar issues. The Olympus OM-1, The Nikon F and the Canon FTb both suffer prism de-silvering due to foam around their prisms degrading and they aren’t the only ones to suffer from these kinds of issues. Thankfully the issues caused be degrading foam are almost always resolvable with a full service. So long as the foams decay is halted before anything is ruined beyond repair.

The biggest killers of old cameras are battery leaks, corrosion and foam decay. Foam contamination is easy to fix usually (so long as its not eaten the prism). Battery leaks (the worst crime to cameras of all) and bad corrosion can be fatal or at least prohibitively expensive to resolve.

Battery Leaks

One of the worst killers of old cameras is the classic battery leak. These can be far more destructive than many buyers and owners often realise. Cleaning the battery chamber is easy but fumes from decaying batteries can cause problems further inside the camera. Even I have been surprised at times. It’s another lesson in just what can be hiding even in cameras which appear fine from the exterior. Here’s a few pictures from the interior of two Minolta SRTs which contained battery leaks. Both would run albeit with some issues but the battery corrosion wont fix itself and left alone will eventually cause problems.

Minolta battery leak — Evidence of a battery leak – you could clean the battery chamber but removing the base reveals worse problems…

Camera battery leak — …in this camera the battery leak had destroyed the shutter safety interlock and caused issues for the mirror gears.

Battery leak issues in cameras — In this camera fumes had migrated upwards damaging the meter pulleys in the top of the camera.

Corrosion

The third of the triumvirate of camera killers is corrosion – this is usually in partnership with decaying foam and/or battery leaks but can be down to just bad storage. Like foam, corrosion can be a hidden killer. Cameras which appear fine from the exterior appearance can often be hiding very severe corrosion internally. The camera may even appear to work, at least in terms of winding on and going click but underneath the skin it can be very different story. Unfortunately most cameras are very intolerant of corrosion. The mechanics inside are akin to a mechanical watch and rely on well regulated and lubricated precision parts and these are not rust resistant.

Corrosion in a camera — …Amazingly it would run but it’s no surprise the shutter was running poorly.

Internal corrosion in camera — From two other cameras – corrosion on the aperture follower and a rusted washer.

The pics above illustrated what can be lurking underneath that shiny exterior. The corrosion in one of these was severe and worse it was firmly entrenched in the shutter mechanism which relies on being clean. Other cameras have shown similar issues at times. Even small parts can be critical to the cameras operation. The small washer pictured above would cause the mirror to fail to reset properly. The corroded aperture follower could cause the meter to misread. A vintage camera is like a fine time piece and needs maintenance and care – few get it.

The Verdict

In many ways the safest cameras with the least foam tend to be very late model electronic cameras like the Minolta X-700 which uses almost no foam internally and none thats critical but late model electronic cameras like the X-700 were often built with plastic gears which are prone to failure, and critically, the electronics tend to be their weak spot. You can almost always clean foam in a service but theres not much to be done if a custom chip has failed or the main circuit board has cracked.

So wheres the crime? Well the crime could be laid squarely at the door of the manufacturers for using a materials which would degrade badly but in fairness I very much doubt whether any manufacturer ever imagined their products still in use 40-50 years after they were sold.

No, the real villains of the piece are todays camera buyers and users- The manufacturers prepared the crime but todays camera users are the ones committing it by failing to accept that these things are old and need servicing.
The most often heard defence against either buying a fully serviced camera or getting your camera serviced is that it’s expensive but it really isn’t that much in the grand scheme of things. As hobbies go classic cameras are relatively cheap. £200 would get you a fully serviced classic camera – less than the price of the cheapest digital you could lay hands on. I would say no one is making film cameras anymore but Pentax are and look at the price they are charging. £500 for a half frame point and shoot! Is it really so much to pay for a full service on your beloved classic?

While mentioning the new Pentax film camera I have read that Pentax have designed it with repairs and servicing in mind rather than designing it like a late model point and shoot which are almost impossible to repair. I just wonder how many of todays shooters will ever bother. Based on experience with classic gear I suspect not many which is a shame. Without viable film cameras then film photography will die – I think that would be a shame – maybe you do too.

I’ll discharge the jury at this point and, if you still wont get a service, I’ll pass sentence on you to expect dud photographs and a life sentence of endlessly complaining on social media that your £30 camera from eBay ‘is perfect apart from…’ I’ll also sentence you to hard labour packing up another dud camera and standing in a post office queue to return it.

Learn Camera Repair – Although film is making something of a come back, one of the areas that is a huge potential stumbling block is the fact that most professional technicians are now either retired or close to retiring. In the UK over the last few years a whole bevy of some of the most expert repairers have closed up shop leaving classic film camera buffs with few options. Some whole marques and models are now almost unrepairable and with the so often heard advice of ‘just throw it away and buy another’ the available pool of viable cameras will only get smaller.

So how hard is it to do it yourself? What do you need to get started? Is it all worth it? In this article I’ll give you a walk through of my own journey and try to point out some of the pitfalls in learning repair. Now I don’t pretend to be the greatest, the wisest or even universal – after all it’s as big a folly to claim you are universal as it is to claim you are unique.

So how hard is it?

“Is it hard? Not if you have the right attitudes. It’s having the right attitudes that’s hard”

Robert M Persig – Zen and the Art of Motorcycle Maintenance

Learn Camera Repair - X-700 with top removed

If you’re talking replacing light seals or cleaning a battery terminal it’s not very hard at all and indeed some of the more straightforward issues are easily solved with the help of articles and web resources (I publish a few on this site) but if you’re talking actual repairs and full on CLA work (cleaning, lubrication and adjustment) it’s a fair bit tougher.

I’ll tell you what learn camera repair isn’t and maybe that will scare a few people off and save them time from reading the full article. It’s an approach I learnt from Tarkovsky the director of the Soviet Sci Fi film Solaris – Tarkovsky put a huge section of film in just after the start of the movie of a seemingly endless car journey – it’s intention was to use an excruciatingly tedious and dull section of film to drive the dull or unwilling to invest type people out of the cinema as, in Tarkovskys view, they would be unlikely to understand or appreciate the rest of the film – how’s that for stunning condescension. I’ll try to be a bit kinder though.

I can tell you more quickly what camera repair isn’t and it’s not;

Buggering about aimlessly hoping you can make it work.
Pouring lighter fuel or WD40 into a camera or lens based on ‘wotsisname’ on Facebook’s advice.
A quick to learn side hustle with riches at the end of it.

So how do you get started?
Well there are two paths to follow – I can only truly relate my own learn camera repair path but my own journey may give you some pointers.

“Long is the way and hard, that out of Hell leads up to light.”

John Milton – Paradise Lost

The first path is you download the Society of Photo-Technologists (SPT) courses and do the theory and practical lessons. The SPT course is very good but you will need to acquire some cameras to do the practical parts of the course with. It’s a long hard road for sure but will give you a good grounding. The course is available at learncamerarepair.com and will give you a solid block of know-how of different types of cameras and their associated shutters, a grounding in electronics and of course critical know how about lens repairs.

The second route, and the way I chose is the school of hard knocks and hands on. Which one works best is really down to how you learn best. For me I never was much one for reading books and theory and will always learn faster through my hands. I like to think of myself as a kind of technological gypsy. Usually I can figure stuff out from any machine just by playing with it, taking it to bits, experimenting, and putting it back together. Now that sounds dangerously like ‘buggering about’ which I cautioned against at the start of the article but it’s more a case of taking pictures and notes, watching how it works by observation. Comparing to service manuals and then reading some theory if I can’t work it out.
Confucius wouldn’t have even known what a camera was but his third route to wisdom is very true if you’re doing the same approach as me.

What I will say about my approach is you will almost ALWAYS need a service manual because not everything inside a camera is obvious and of course for some of the set-up and tuning you will need the manufacturers guidance as to what tolerances are allowable and how to align certain parts etc. Bear in mind even relatively simple mechanical cameras may contain around 1500 precision parts and springs. If you’re going to do the “learn as you go” approach you need to have a pretty good grounding in mechanics and basic electronics and a pretty solid understanding of how the camera actually works at the start. If you lack those then the SPT course is probably your better route to knowledge.

Bear in mind the manufacturers service manuals were mostly designed for people who were already proficient at managing camera repair – they are not designed to be a training course for the camera. Without some practical experience the service guides are often no help at all offering little more than exploded diagrams.

Now, I said I generally learn faster using my hands on approach, BUT I also read everything there is to read. I joined forums, read everything that was posted and took onboard advice from genuine acknowledged experts. The best forum for this is the Learn Camera Repair Facebook group because it has genuinely experienced folk in there and not bodgers who are always suitably reined in. Why didn’t I do the SPT course myself? The answer is I originally intended to and being naive at the start imagined it couldn’t be that hard to do. After some time I realised that given my age (ancient) and limited time I could never hope to get competent across a large range of cameras so I specialised. It’s the old, old saw about get big, get niche or get out. I chose niche. In my case I simply won’t live long enough to learn every camera and shutter mechanism – to get where I am now, which is competent on a small handful of camera types and lens repairs has taken 5 years of learning and experience where I spent every weekend working on cameras and quite a few evenings too. Like any serious hobby camera repair takes time and there are no shortcuts.

If you have a passion for a particular camera this approach of just learning a single type or sub-group may work well for you as you can specialise. If you want to be a generalist and/or have a real breadth of knowledge the SPT course is an absolute must.

Learn Camera Repair - Chinon 50mm Lens — Learn Camera Repair – One of my early successes. A Chinon 50mm. The lens was a wreck but restored beautifully

Learn Camera Repair - 50mm Chinon lens — Learn Camera Repair – Another early successes. A Chinon 50mm. The lens was a wreck but restored beautifully

My approach was to acquire broken cameras and lenses, download the service guides or even better a tutorial if one was available on the camera and go from there. Initially I worked only on lenses as I already had some experience from working with telescope optics. For lenses and cameras get some hands on and learn how the mechanism works. Good general advice is not to assume a You Tube video is right or sensible or even smart no matter how many followers the YouTuber has – There is much bad practice shown on You Tube videos by people claiming expert status on the basis of ‘likes’ and some of these are positively clueless. Not every YouTuber is an idiot or bodger but unfortunately at the start of your journey you will be hard put to tell which is which. Bad advice extends onto many forums and web pages as well unfortunately. My rule of thumb is don’t trust anyone less experienced than yourself.

“All men are not equal in wisdom – the half-wise are everywhere”

Hávamál

I managed to mash up a Fujica ST605 at the start of my journey from following some You Tube advice which was seriously duff and later on an auto Rokkor after a You Tube video I watched forgot to mention a fairly critical element of the disassembly. I was sufficiently au-fait at the time of the near disaster with the Rokkor and good enough to get myself out of a hole dug by a combination of a less than accurate You Tube guide and my own over confidence about working with a similar model of lens. For a less experienced person it might have been a worse disaster and yet another lens consigned to the bin.

Learn Camera Repair - Minolta XG-M — Learn Camera Repair – An early failure – in over my head with a Minolta XG-M – it’s all learning experience.

Learn Camera Repair - Minolta Auto-Rokkor Lens — Learn Camera Repair – A close call when an online video turned out to be in error. Lucky I was good enough to resolve the issues arising.

My journey into the black art of camera repair started by me bagging up anything I could from charity shops but quickly found it’s a hard way of doing it. Some cameras are much harder than others to work on and doubly so when there are no service manuals available and you are on your own with no support and not enough experience to guide you. I have had disasters early on in my own learning experience and you will too for sure – the disasters are a learning experience in their own right. If nothing else you will know that a certain make or model of camera is beyond your ability (at least for the present). It’s a truism that we learn most from our failures – though you don’t want to take that principle too far.

So that’s lesson Number 1, don’t get into this thinking you will be able to fix any camera that ever existed. Most of the pro level amateurs like me tend to specialise in only a few cameras where they have built up some solid experience over time. The real expert older techs can fix most things but they have had 40 years or more to build up the experience and they learnt in a safe environment with more experienced people on hand to help out at the start of their journey PLUS they often had factory training – little of that is available now.

Dip a toe in the water first … so my advice would be buy a camera that has a known issue. Minolta X-700s for instance have known issues with their capacitors. Buy a banger and see if you can fix it. It may have more than the capacitors at fault so you may need to go a bit deeper. This is how you learn to deal with the more common issues. You have to see every camera you buy on this journey not as a possible money maker and a quick side hustle (eg you paid £10 for it but fixed it so you can sell it for £100) but a lesson that’s costing you £10 to learn how to fix that model of camera. I confess when I started I had not thought it would be so hard – experience has shown otherwise. For the hands on learner you should ideally look for something that’s purely mechanical. Find a CLA guide and the service manual and follow that – it will give you experience of taking most of the camera to pieces and learning how parts inter-operate. Be prepared to have to pay for some of these resources.

I learnt the very most about the Minolta SRT-101 from buying a banger that I was sure I could fix because I had already worked on so many of them – this as it turned out was a big mistake! The banger had so much wrong with it that I was initially minded to scrap it for spares but decided to use it as a learning tool. £30 wasted – not a bit of it – it was a massive education for me. There’s no virtue quite like necessity and few better teachers than experience.
I learnt lots from that camera but the biggest lesson was lesson number 2 – always keep confidence balanced a safe distance from arrogance and don’t get too big a head. Ego is a problem in any repair work – stay humble.

Learn Camera Repair - Minolta SRT-101 Repair — Learn Camera Repair – Ms Troublesome – maybe the worst SRT I ever worked on but I also learnt the most from this.

Learn Camera Repair - Minolta SRT-101 — Learn Camera Repair – Success – a very troubling repair but persistence always pays off.

Now a word of caution here if you are going to buy a camera to learn with make sure it’s something where there are online resources – manuals, service guides and ideally a tutorial. There’s no point buying a rare HokkiKokki STX-7 if there’s no service guides because you will really struggle and there may be little or no expertise online to help. Another aspect of this is spares availability. Whole legions of cameras are now facing extinction because of shortage of spares. This may be because the camera in question was never very popular so finding a spare is hard (Some of the later Yashica 35mm SLRs for instance) or it may be that the camera is super desirable and consequently even people selling a complete wreck want lots of money for it (Minolta XD/XE and Nikon F2s for example). If you’re going to learn at the start my suggestion would be something you can acquire cheaply both as the learner camera and as a spares source. I ended up doing Minolta SRTs. Not out of any particular passion at the start for them but simply because they were available at a low price and one of the first cameras I ever had to REALLY fix was an SRT which gave me my start. As time goes by you will be able to apply the knowledge from one camera to another.

The experiences of trying to fix any and every camera is what forced me to go niche and just work on a small handful of models. and there’s lesson number 3 – if you butterfly about trying to manage all comers you will more likely fail more often than you succeed. You need to build confidence first and confidence comes from having success. Once you have built on some success you will feel happier and better able to manage something new.

Choose your poison?
There is a world of difference between older mechanical cameras and later electronic ones. For electronic cameras you need a fair degree of electronics know how to stand a chance of fixing them. Their mechanics are, at least in some respects, similar but even relatively simple electronic cameras can be a nightmare when things aren’t working.

Minolta SRT Repair — Learn Camera Repair – Old school mechanical cameras – springs, strings and a profusion of nuts and bolts.

Minolta X-700 Repair — Learn Camera Repair – Late 70s electronic cameras – less nuts and bolts but equally challenging.

What you decide to work on is very much a case of which you feel most comfortable with. The standard camera to learn mechanical SLRs on is the Pentax K1000 which is a simple mechanical camera with minimal electronics. It’s ideal in many ways as it’s entirely mechanical so you can actually see how its works. I transitioned from strictly mechanical cameras like the Pentax K1000 and the Minolta SRT series through to some of the electronic marvels. For me, even with my electronics know how, I think I might have struggled with an electronic wonder without the experience gained on more simplistic cameras.

What do you need to get started?

“An adequate supply of gumption is the first and most important tool. If you haven’t got that you might as well gather up all the other tools and put them away, because they won’t do you any good.”

Robert M Persig – Zen and the Art of Motor Cycle Maintenance

Attitude and will are the most important tools, but with that said you will get nowhere without the right physical tools for the job. The bare minimum will be a good set of screwdrivers, both JIS and cross headed/flat bladed types, a lens spanner and some rubber cones. Don’t rush in and buy every tool going. I started small – just some good quality tweezers, fine wire cutters, some fine nosed pliers, jewellers drivers and (for Japanese cameras) some JIS screw drivers. Over time I have added extra lens spanners for specific tasks, slotted drivers to deal with specialised nuts and fittings, rubber cones (an absolute must for many lenses). In addition you will need various chemicals and lubricants. There is a complete listing of tools and chemicals at the end of the article with recommendations. It’s best to start small and build up slowly. As with any hobby buy the very best tools you can afford – they will last longer and will not cause you additional grief in repairs. I had something of a hot start as I used to work in electronics so already had a good selection of precision tools and soldering gear.

The cost of tools… What do you need?

The cost of tools is what puts most people off as a hobby. While you can often do some repairs with just a few micro-drivers and a lens spanner for full on work inside most camera bodies you need a wider variety of tools. The more different types of cameras you work with the chances are the more tools you will need. Some of these you will have to make yourself because manufacturers often employed special tools which of course are no longer available.

To really manage repair and servicing work you also need a shutter tester and one that’s capable of measuring curtain speeds if you are working with 35mm camera with focal plane shutters. Many low cost testers on eBay and similar won’t help as they can’t measure curtain speeds and many of these will be useful only for a rough and ready assessment of the shutter speed as they lack accuracy.

And here’s lesson No.4 really – gearing up to do camera repair is expensive. It’s not a cheap hobby and you will struggle to find buyers for your work once you are able to turn out fully serviced cameras. Just look at Facebook groups and see how often the advice is not to bother with repairing a camera and just buy another cheap one on eBay. A fast and profitable side hustle is definitely not what you will find.

My short picks for tools for anyone starting out would be would be…

JIS Screwdrivers — JIS Screwdriver set from Polar Bear Camera – a perfect set of JIS and flat-bladed drivers to get you going

Lens Spanners — From left to right lens spanners from Amazon (cheap) from Microtools.de (good) from SK Grimes (The best but expensive)

Rubber Cones — Rubber cones from Japan Hobby Tools – The best there is

Rocket Blower — Rocket blower and fine sable brush

These will allow you to work on some lenses and with a few extra bits like a soldering iron and some snipe nosed pliers, wire cutters and tweezers will get you through much of the work on many cameras and lenses. You may need an additional set of watchmakers slotted drivers to deal with some lenses.

You will of course have to invest in assorted materials like light seal foam, lithium grease, moly grease, Nyoil, Isoprop Alcohol, Hydrogen Peroxide, Ammonia and you won’t believe how many cotton buds, cotton wool balls and cocktail sticks you will get through during the average repair. To go with the materials you will also need applicators. I favour syringes and watchmakers precision oilers. You will, if you take up camera repair, have at last a real use for old toothbrushes especially when it comes to cleaning old lubricants.

Now as you progress through repairs you will sooner or later need test equipment. In order to set up most mechanical and electronic SLRs you will need a shutter tester capable of measuring both curtain speeds and shutter speeds and to set up meters on many cameras you will need a calibrated light source. These two items will be the most expensive single part of your tooling and the element that puts most people off doing serious repairs.

Spares
Almost no spares exist for many cameras from the golden age of film cameras. Your only chance of spares is cameras which are non-repairable. This is another good reason to stay niche. If you’re trying to spare for lots of different cameras your going to be forever held up waiting for a suitable donor camera to appear. If you stay niche you will very quickly find spares from cameras you messed up while learning. My advice is NEVER, EVER throw anything away and always treat a donor as if it was a worker. Mashing things up to get the bit you want right now usually means you will bust stuff that’s going to be useful later. Broken and non-repairable lenses and bodies are a useful source of spares not just for the critical stuff like focus screens but for the huge assortment of small screws, washers, springs etc. Cost of donor bodies is something you should consider when choosing what cameras and lenses to work on.

Shutter Testers and Calibrated Light Sources – This is where it gets expensive!

ZTS V shutter Tester — Zimmerman ZTS V with calibrated light source – Professional shutter testing but it doesn’t come cheap!

The Reveni Labs shutter tester. If your serious about repairs it may be the answer to your prayers!

There have been various low cost shutter testers developed but few of them are capable of the accuracy required. Old school techs still rely on gear made by Kyoritsu but 2^nd hand units are scarce and expensive – you can expect to part with around £3,000 – £5,000 for a working one. The other most common tester from the same period is the Zimmerman ZTS but these are rarer than hens teeth and you can expect to pay around £650-£1,000 for one IF it’s working. The problem with both of these pieces of kit is they are old and reliability is always going to be an issue.
Early on I bought the Phochron tester which was a Crowdfunded bit of kit. It’s rather good and subsequent testing comparing it with my pro level ZTS V tester has shown the Phochron comes very close in terms of accuracy for most shutter types (though it doesn’t handle Minolta SRTs well in my experience).

Phochron Shutter tester — The Phochron – reasonably priced and fairly accurate but now out of production.

The Phochron is now out of production but they do show up for sale periodically for around the £200 mark and they are very accurate – close enough for most amateur level repairs. The other most current tester is the new Reveni Labs tester which sells for around $400 Canadian dollars.

The Reveni Labs https://www.reveni-labs.com/reveni-labs-camera-tester product is probably the closest anyone is going to get for a production made, ready to go tester that can offer pro level features and I fully intend acquiring one myself fairly soon as it is capable of testing for even more conditions than my ancient ZTS V.

You can see from this that learning repairs and doing it right is quite expensive and time consuming. The average CLA time for something like a Minolta SRT-101 is around 6-8 hours) and the demand really isn’t there so if your planning on learning repair you have to be doing it for love not money. If Mammon is your God then you will be disappointed. There are professional techs making a living from the art of camera repair but they tend to ply their trade on the more exotic cameras for which aficionados are willing to pay for.

That’s not a counsel of despair and there are, like me, several people learning and doing good work and I would always encourage people to learn the trade/art/dark magic whichever you prefer but I would also never want to get someone into a financial black hole in a search of El Dorado. You MUST see this, at least in the first phase, as a hobby NOT a money making opportunity.

Summing Up

“There is a great satisfaction in building good tools for other people to use.”

Freeman Dyson

So there you are – what you need is patience, practice and a lot of reading plus taking the occasional slap on the head either from a camera you couldn’t repair or a sudden bang to the head when an experienced expert tells you to shut up and listen. I did say ego is always a drawback so don’t get huffy when an experienced pro gives you advice.

On the upside if, like me, you find it rewarding at an emotional level (because as I explained I doubt you’ll find it rewarding in terms of cash in the bank) to fix old stuff and give these beautiful cameras a second life then you will find much support from others doing the same and who knows – you may end up being the only person doing repairs to a certain model of camera and you may just find a pot of gold out there. If not you can take satisfaction from the skills you acquire, the friendships you make and knowing you have helped preserve a part of 20th century industrial history.

I hope that’s given some of you reading this an insight and maybe a real desire to learn camera repair and get to grips with what can be a very rewarding hobby.

CLA Guide and Tutorial for Pentax ME Super

To help beginners to camera repair I have recently made available several guides to some common cameras which will walk you through basic servicing with step by step instructions and pictures. These are available HERE.

Tools List
The list I have assembled are the tools I use most frequently excepting some home made tools for special applications.

Hand Tools

JIS Screwdriver Set – For all Japanese cameras and lenses – Budget
JIS Screwdriver Set – For all Japanese cameras and lenses – Premium (the set I recommend)
Watchmakers screwdriver set – Many lenses and cameras have micro grub screws and slotted screws
Rubber Cones – Essential for many lens repairs
Gum Rubber Bung from a wine flagon – Removing trim rings from cameras
Lens Spanner – Essential for lens work
Lens Sucker – Essential for lens work
Exacto Knife or similar – For cutting lightseal materials)
Metal Ruler – For cutting light seals
Cutting Mat – For cutting light seals
Tweezers – General purpose use
Reverse tweezers – useful for soldering
Small snipe nosed pliers – General purpose use
18W Soldering iron – Internal wiring in camera bodies
Soldering iron stand with cleaning sponge – Essential for good soldering
Solder – Internal wiring in bodies
Solder sucker – I prefer a solder sucker. Buy the very best. Cheap ones NEVER work!
Desolder braid – for desoldering
Rocket blower – General purpose and lens cleaning
Sable brushes – for applying grease, cleaning items
Syringes – For applying glue and lubricants
Watchmakers oilers – For applying fine oils like Nyoil
Scissors – General purpose
Old toothbrushes – For cleaning
Micro hex drivers – Some camera bodies use micro hex fittings internally
Ice Cube Trays – for storage of small parts)

Test equipment

Multimeter – Essential for testing electrical circuits in many camera bodies
Shutter Tester – Essential for almost any camera body. For focal plane shutters it must able to assess curtain speeds.

Chemicals and materials

Isoprop Alcohol – General cleaning
Acetone – Removal of threadlock
Hydrogen Peroxide – Fungal removal from lenses
Distilled Water – Cleaning of optical parts
Ammonia – Fungal removal (I almost never use it)
Baader Optical Wonder – General lens cleaning
Microfibre cloths – Cleaning of optics
Cotton buds – Cleaning of parts
Cocktail sticks – General purpose
Cotton wool balls – Cleaning
Nyoil – Essential for fine lubrication
Helimax XP – General purpose lens lubricant
Lithium grease – Lubrication
Dry Moly – Lubrication (I seldom use it)
Graphite Powder – Lubrication (I seldom use it)
Light Seal Materials – Camera bodies
Optical felt – Camera body lights seals

Misc.

A collection of broken cameras – NEVER throw anything away. Non-repairable cameras are a goldmine for small screws, shims, springs, washers etc which are often hard to find.

Minolta MC-X Rokkor PF 50mm f1.7 Lens Repair

A step by step repair and servicing guide for Minolta Rokkor PF 50mm f1.7 MC-X Series lens.

The MC-X Rokkor PF is actually part of a series of lenses loosely known as the MC-X series. These were a kind of halfway house between the earlier MC Series and what would be the last Manual Focus series from Minolta, the MD series.

The MC-X series were designed with the Minolta X1 in mind so lack the second lens tab required for full program mode on later Minolta cameras. The MC-X series produced some of the finest manual focus lenses ever made including the 50mm f1.4 PG but as always there were budget lenses also created like the 50mm PF 1.7 and the 50mm f2.

A note of caution here, the MC-X series quite often bear very little relationship to each other in regards of internal design. The 50mm f2 for instance is quite different..

Copyright 2024 High5Cameras,
Free to use, copy and distribute so long as no charge is made for use,
distribution or access and authorship and web address is freely acknowledged.

Many Minolta MC and MD series lenses are very simple to service and there are general guides for the 50mm versions on this site : –

This is not the case with the MC-X 50mm f1.7 which is a horror lens to work on. ALL lenses in this series are best left to people with lens repair experience as they often contain booby traps for the unwary. The 50mm f1.7 is no exception. Without adequate testing gear like a calibrated light source and a shutter tester capable of assessing accuracy of exposure this lens is very hard work indeed. Certainly NEVER tackle one of these without a working example to refer to.

You will need some small containers for screws. I use ice cube trays for my work and use a sharpie pen to scribble as to which screws are in which cell of the container.

This lens was a scrap item and the guide was built during examination as a preparation to doing a viable lens. On this lens the front element has been wrecked and the focus feel was over stiff.

Read through the whole guide before starting so you know what you are doing and always be mindful of what you are doing when you start work. The most common beginner mistake is to press down on the lens and forget that the opposite side is exposed, this can lead to snapped off aperture levers or wrecked front optics. Keep the lens capped on the opposite side to the side you are working. Work slowly and carefully and dont rush. There are no Olympic sports involving the fastest lens rebuild and a rushed job will lead to mistakes.

You will need the following tools and parts to carry out repair and servicing of the MC-X Rokkor 50mm f1.7

Minolta MC-X Rokkor 50mm f1.7 Repair Guide – Disassembly

First remove the rear lens group. You will need a good lens spanner to get this out as they often have a thread-lock/lacquer applied. If it doesn’t shift quite easily leave it alone. There will be an opportunity to remove it later but it’s easier to manage if it comes out at the start.

Use the spanner on the outermost spanner slots.

Minolta MC-X 50mm f1.7 removing the beauty ring

Cap the rear of the lens and turn it over. Remove the beauty ring. There are spanner slots on the beauty ring but a rubber cone is less harmful.

Note – on the F2 version of this lens the beauty ring is glued into place and not threaded.

The beauty ring will unscrew with even pressure applied using a rubber cone.

Removing the filter ring on the MCX Rokkor 50mm f1.7

The filter ring needs to be removed next. This is retained by 4x JIS screws. Do not remove the screws visible in the cut outs at this stage. Extract only the filter ring retainer screws.

Set the focus ring to infinity. You need to make sure this stays there until you can get some measurements of the helicoils and also mark the helicoil positions.

On this lens getting the focus to stay in place was easy – the focus was very stiff – almost stuck in fact. On some copies the focus may be excessively loose.

Removing the front optical group from the PF 50mm f1.7

The front lens group can now be removed. You will need a lens spanner for this. Use the spanner on the outermost slots only.

The front optical unit will now pull free. You will usually find at this point oil traces over much of the interior. Normally the inner optical surfaces will have oil haze on MC-X types although their diaphragms almost never suffer oil contamination.

And here is the big problem with the MC-X series. On every other Minolta lens the diaphragm is ‘keyed’ to a certain position which makes managing the lens quite easy. The MC-X series have floating diaphragms. In this case the diaphragm is held into its position by a circular retainer which is held by 4 screws. With the retainer removed the diaphragm is free to ‘float’ to any position. It gets worse – you can’t mark the position easily because the only adjacent parts are also able to rotate.
Your choices are either make markings of absolutely EVERYTHING (relationship of diaphragm position to focus helicoil and also mark the focus helicoil entry and exit points and their relative depths) OR manage the lens later using a calibrated light source and a shutter tester capable of assessing exposure errors and using a working copy to compare with. This is why the MC-X series is not a lens for beginners.

To remove the diaphragm remove the four JIS screws that secure the retainer ring.

Here’s the retainer ring being removed. The diaphragm is now free to turn in either direction without respect to the aperture control ring.

Removing the diaphragm from the Minolta MC-x 50mm lens

With the retainer removed the diaphragm will simply pull free from the lens body.

If you were unable to extract the rear optical group earlier it will come out with the diaphragm which will allow you to apply some Isoprop to it to break down any threadlock. Be careful because the back of the diaphragm contains aperture control stop down lever which is quite fragile.

The rear trim ring on the MC-X Rokkor PF

Now it’s time to get the rest of the lens to pieces. Start by removing the rear trim ring/cover. This is retained by three tiny slotted head grub screws.

WARNING – these are VERY small.

Here’s the rear cover being pulled away after the three grubs screws are removed.

Minolta MC Rokkor PF f1.7 50mm aperture controle

Set the aperture control ring to f1.7

The rear lens retainers on the MC-X series

With the lens set to f1.7 you will be able to see the lens rear assembly retainer screws through the cut outs on the rear of the aperture control ring.

Set the lens to infinity focus before going further and keep checking that it hasn’t shifted as you go forward.

Remove the four JIS screws. These hold the rear of the lens to the body.

Seperation of the rear of the MC-X Rokkor 50mm f1.7

The rear portion of the lens will now separate from the body.

MC-X lenses also have another difference to any other Minolta manual focus lens. This screw on the side of the aperture control ring is an access point for the small ball bearing which provides the click stops for the aperture.
You do not need to remove this screw unless you wish. You will need a very unique driver to extract it without damaging it. I use a driver designed for slotted Nikon lens screws.

With the screw removed you will find the standard 1.2mm bearing. The spring to hold the ball is also inside the screw body.

When reassembling this does provide an easier way to get the bearing back into position but it does require the use of a special screwdriver that has a vertical cut blade and is very thin but quite wide.

Looking inside the aperture control ring you will see this curved piece. This controls the opening of the diaphragm.

Unfortunately along with the diaphragm being free floating this part can also affect the diaphragm opening. If you wish to separate the rear portion of the lens getting this aligned on rebuilding will be very troublesome.

To remove the aperture control curve, turn the lens over and remove the two screws. Make sure you mark the position of the curve. It will be critical later.

Unless you really, REALLY need to remove this you are best advised to leave it alone. Getting the aperture right is hard enough without having to worry about getting this aligned as well.

The aperture control curve can now be manoeuvred out. Note its orientation.

Separating the rear components of the PF 50mm f1.7

The aperture control ring can now be removed from the lens body. When you do this take care as the small ball bearing can fly off. It’s best to do this in a large Tupperware box or a bucket to reduce the risk of losing the bearing.

If you did not remove the screw fitting earlier that retains the spring and the ball bearing, extract the spring now using a cocktail stick. The bearings are replaceable but the springs are not, so store the spring and the bearing safely. I use an old film container.

Remove the focus barrel by releasing the three JIS screws. Be careful as each screw has a very small washer underneath it.

With the screws removed the focus barrel will simply slip off.

It is assumed you set the lens to infinity focus at the start or at the checkpoint earlier

Measure the helicoil gaps and make a note. You need measurements between the inner (black/silver) helicoils and the brass helicoils plus the brass helicoil to the silver lens body.

You also need to mark their relative positions AND their exit points as they separate.

Remove the three screws that retain the focus helicoil lock tab.

The helicoils can now be unscrewed and cleaned.

With the lens almost completely stripped you can now clean all of the lens body work.

Unless you have issues with the diaphragm simply wipe its exterior surface clean and run a cotton bud around inside AVOIDING the aperture blades. Normally I would suggest stripping an oily diaphragm but the MC-X is such a nasty lens to work on I would most likely use a freon free spray degreaser and then soak in Isoprop.

The rest of the lens body parts can be cleaned with Isoprop or hot water and a mild detergent. When I service a lens EVERYTHING gets cleaned. For final finishing I flush all parts BUT NOT THE INNER HELICOIL AND DIAPHRAGM under cold water and then blow dry.

The helicoils and lens body thread for the outer helicoil are then chased out with cocktail sticks to ensure that all thread surfaces are free of dirt and contaminants. Finally make sure the helicoils are running smoothly without lubricants to assess if any threads are damaged. Very often people have seen You Tube videos and poured lighter fuel in the lens to get the focus moving. This is a fast fix but creates long term issues with excessive thread wear and as a result you may need extreme measures like a lapping compound to polish out any defects in the thread.

Minolta MC-X Rokkor PF 50mm f1.7 Repair Guide – Reassembly

When reassembling do not over-tighten any screws. This lens can be awkward and you may end up disassembling. The name of the game is lightly tighten stuff down. Test the lens and if all is well go back and retighten screws after you are sure all is working well.

First lubricate the helicoils. I usually use Helimax XP for most Minolta lenses as it provides a perfect damping while retaining a good feel. It’s also able to work at both high and low temperatures and resists migration.
The outer metal helicoil needs only a light coating while the inner helicoils needs a slightly thicker dose. Getting the feel right is a bit of witchcraft and comes with experience so you will need to experiment to get the feel right. The one good thing about the MCX series is they are not super fussy about dosing on the lubrication. An even thin coat on the brass outer helicoils and a slightly thicker coat on the aluminium inner helicoil will be fine.

When re-assembling the helicoils the name of the game is to get the helicoils at the same distances from each other and the body as you measured earlier and also aligned with the marks you made PLUS…

Getting a good alignment with the focus lock tab. Assuming you marked both helicoils with their infinity position and measured the distances correctly they should align at the locking tab position correctly. These screws can be tightened down if you are sure about the focus alignment

Refit the aperture control ring to the lens body. Note that there is a cut out in the aperture control ring that must align with a brass screw on the lens body. This acts as the end stop for the aperture control ring.

You will need to make sure this is aligned. You will need to replace the spring and ball bearing prior to this. Apply a little grease to the ball bearing to ‘glue’ it to the ring and then apply the ring at an angle to trap the bearing and the push the rest of the ring into place. This is the same procedure for most Minolta lenses. I didn’t get a picture of this but you can refer to any of the other Minolta lens guides on the site to get an idea of how to do this.

Refit the aperture control curve – notice how the silver stud on the aperture mechanism fits against the curve. You will need to move the sprung aperture part out of the way to get the curve in place.

The positioning of the curve is critical and will affect the lens aperture response.

The curves position is regulated by the two screws. If you made markings align as best as you can at this point…

Replace the screws that retain the curve. Don’t over-tighten these as the fixing point is plastic and it’s easy to strip the threads. You only need as much pressure as you can exert between thumb and forefinger on the screwdriver barrel.

Replace the focusing helicoils to the lens body. Note that the body has a cut out for the focus lock tab. These have to align.

Repalcing the helicoils to the lens body

With the aperture set to f1.7 and the lens helicoil focus tab correct orientated to the body cut out the fixing screw holes will be visible.

In the picture a cocktail stick is holding the hole position to the slot and blocking the aperture ring from turning out of position.

Replace the screws that retain the lens body. These can be done tightly but dont over tighten. Remember the screws holes are threaded into aluminium and it’s easy to strip threads out.

During the following phase keep your wits about you. You can’t have the rear of the lens capped so remember this because the fragile stop down lever is exposed and subject to breaking if you press down on the lens.

Note the cut out in the aperture lever (in the picture it’s just to the right side of the stop down lever on the rear of the lens).

The diaphragm barrel - Rokkor PF50mm f1.7

The diaphragm control lever needs to be positioned into the cut out in the aperture lever.

Here is the diaphragm barrel being replaced. Unlike an MC series there is no flat on the barrel as an alignment point.

You can now see that by rotating the diaphragm barrel the diaphragm will open and close. You now need to tune this. At wide open (f1.7) the aperture blades should be just slightly out of sight behind the diaphragm mask. At minimum aperture (f16) the aperture should close down. Across the range the aperture should open/close evenly with each change of aperture stop.

This is a particularly tough job with the MC-X series because both the position of the diaphragm barrel AND the positioning of the aperture control curve will affect the aperture opening. Without a known good lens to compare with this is a very hard job. Even with a working lens it can still be a painful process requiring a lot of patience. It’s a very difficult lens to work with/on which is why I would advise people not to mess with the MC-X series.

I managed getting the aperture right by getting a close visual approximation and then loosely fitting the optical elements. By fitting the lens to a known good camera with reliable shutter speeds I am able to test exposure error at each setting and by seeing the results. I can fine tune the lens. Even with experience and test equipment the MC-X series is no fun to work on.

Assuming you are happy with the aperture/diaphragm performance you can now refit the diaphragm retainer…

FIT THE REAR CAP TO THE LENS NOW – YOU DONT WANT TO BUST THE STOP DOWN LEVER!

…and replace the 4x JIS screws to hold it in place.

Replace the rear trim ring with its grub screws. The rings fixing position is not specific but it’s best if you can to line it up with the original positioning. Normally there will be marks on the lens body where the grub screws were. If not don’t worry and just refit as is.

Replace the front optical unit after giving its inner surface a clean and blowing out the lens interior. Do not use harsh chemicals – the MC-X series can have very soft inner coatings. A very dilute Isoprop, breath and a fine lint free cloth gently applied is all that will be needed in most cases.

Unless there are issues like fungus it is best not to disassemble the optical units. There is always a small amount of dust from when they were manufactured and trying to get rid of it usually just means moving the dust around or adding some fresh dust. Tighten the unit down with a lens spanner – it only needs to be hand tight plus a small tweak.

Replace the rear optical unit after giving its inner surface a clean.

Mount the lens to a known good camera and bring the lens to infinity focus. Use a split image viewfinder and get infinity by focusing on something distant. I normally use two radio towers which are around 8 miles away. You can focus the lens using the brass outer helicoil.
DO NOT WIND THE LENS TOO FAR OUT or you will risk disconnecting the inner helicoil from the lock tab.

With the lens at infinity replace the focus barrel so that the infinity mark is aligned with the index mark.

Fitting the focus barrel retainer screws

Refit the focus barrel retainer screws with their washers. As ever do not over-tighten.

Replace the filter ring and refit the retaining screws.

Replace the beauty ring. Take care as the beauty ring is plastic and it’s easy to cross thread this and jam it. A rubber cone works best for this.

The Minolta MCX Rokkor PF 50mm f1.7 Lens

Assuming all has gone well – give yourself some congratulations, have a cup of tea (or the beverage of choice) and get ready to get some great pictures.

The MC-X Series are a tough challenge but I hope this guide will have at least eased some of the way.

This Minolta MC-X Series Lens Repair Guide article can always be improved. If you have any questions and or comments we would love to hear them in the comments below. Mel.

How to clean a focus screen…

How to clean a focus screen: – One of those things that comes up endlessly on forums for classic cameras is ‘How do I clean a focus screen?’ to save my fingers and to try and antidote a lot of bad advice out there I am creating a handy article that I can now link to each time this comes up.

OK before we get started with cleaning the screen lets take a quick look at some of the issues.

WHY DOES A FOCUS SCREEN GET DIRTY?

Well over time like with anything dust builds up. Added to that many of the people asking for help are using cameras that that are 40+ years old. These may be suffering from failing mirror bumpers and light seals. Check out the guide to replacing these HERE.

Sadly the decaying foam from the mirror bumper (and sometimes from other internal foam) leaves fragments of foam and nasty gunk on the focus screen which won’t easily blow off.

HOW EASY IS IT TO CLEAN A FOCUS SCREEN?

Well how tough it is to clean depends a great deal on the camera design, where the dust and dirt is and how dirty the screen is.

Generally speaking it’s best to clean as little as possible but if that dust and dirt in the viewfinder really is distracting then you may well have no choice but to clean.

How hard the cleaning is depends greatly on the camera design and here’s why….

On some cameras the focus screen is removable and is a single piece unit (eg Olympus OM-1, Minolta XD7, Minolta X-x00), on some the focus screen is a two-piece unit but removable (eg Nikon F, Nikon F2). On others the focus screen is either a single part fixed in place (Canon AE-1, Pentax ME) or, on older cameras, a two part system fixed in place (Minolta SRT, Canon FTb and older Pentax cameras).

Minolta X-700 – Harder. The screen comes out but its tricky to do

To clean both top and bottom of the screen the screen needs to come out but it’s possible, with care to clean the most common dust and dirt from the bottom of the screen visible inside the camera with the lens removed even if the screen is non-removable.

You need to consult your own camera manual to decide what is possible.

TYPES OF FOCUS SCREENS

A single part screen is usually just a thin plastic screen that’s fitted under the prism. On a two part screen the screen comprises a Fresnel lens and a condenser lens. Why the differences? Principally down to the advances in production technology for making these. A single piece screen looks flat but is in fact slightly curved as the condenser is part of the Fresnel.

Focus screen types — How to clean a focus screen: A two part focus screen with a condenser and Fresnel in a carrier and a single part screen.

All Fresnel screens and single part screens have two different sides– a shiny side that’s quite hard and faces the mirror and a matt side with the Fresnel grooves which faces the prism.

The side facing the mirror is the hard, shiny side. This is the side you see when you take a lens off and look inside the camera. It’s best cleaned sparingly – a blower brush at most. If something is stuck to it breath on the screen and VERY GENTLY use a cotton bud to remove the particle.

If you are super careful you can apply some distilled water using a cotton bud but be very gentle. The screen is easily marked and NEVER use any chemicals. Some focus screens can cope with chemicals like Isopropyl on the hard shiny side, others will simply melt. The matte Fresnel side will ALWAYS be ruined by applying chemicals.

ISSUES WITH DIRT ON THE TOP SURFACE OF THE SCREEN

On a camera with a non-removable screen the top part is semi sealed. Whether stuff gets on the top of the screen is really down to the cameras design. Minolta SRTs for instance can be contaminated as interior light seals crumble. Others may allow dust to gather behind the screen.

For cameras with a non removable screen how tough it is to clean the top surface of the screen comes down to how tough it is to get the prism out to get access to the top surface of the screen. Some older cameras (like the Minolta SRT and Canon FTB) present some challenges but later electronic cameras can present king sized headaches as they often require their flex circuit boards to be removed to get access to the prism OR the mirror box to come out. Typical culprits for this are the Canon AE-1 and Pentax ME and ME Super and the Nikon F-301 (although the Nikon is very well sealed so getting stuff on the top of the screen is unlikely – at least I have never seen it happen).

You need to be careful with the prism out of the camera. Older cameras usually have their meter needles in top of the screen and these can be easily damaged by excessive blowing or worse someone ramming into the meter needle or meter follower with a cotton bud.

Focus screen seals — Decaying seals around the focus screen will cause contamination of the top of the screen.

Top part of a focus screen — A Minolta SRT. It’s relatively easy to get access to the top of the screen but caution – the meter needle and follower are VERY fragile.

CLEANING A SINGLE PART SCREEN

So lets assume you can get the screen out for cleaning and its easily removable and a single part screen. Your cameras user manual will be the best source of information on this. If you dont have one to hand check out the Mike Butkus site HERE (and dont forget to donate a dollar – Mike is a Saint and worthy of your support).

CAUTIONARY NOTES HERE

NEVER, EVER use Isoprop on a focus screen. You may, just possibly, if you are beloved of God, get away with it on the shiny side but you never will on the matt Fresnel side – the screen will melt and be ruined. Some focus screens are almost impossible to find spares for (Pentax MX and Minolta XD7 for instance) so BE CAREFUL.
I have seen ammonia recommended but having once trashed a rare screen by using chemicals I am loathe to ever risk it again.
ALWAYS hold the screen by its edges and minimise contact with its surface. Don’t lay the screen down on hard surfaces or be inclined to pick or push at dirt on the screen with your fingers. If you muct put the screen down then use either a clean sheet of paper or a soft lint free cloth.
My regime is to slowly step up and only move up a notch if absolutely necessary, a slight imperfection is a lot better than no screen at all.

First off blow the screen with a rocket blower – this will take dust off. Don’t bother with one of those tiny blower brushes so beloved of Amazon and eBay camera care kits – get yourself a decent rocket blower like in the picture.
Use a duck feather gently to brush with (Eugene Pate at LearnCameraRepair swears by this but I have been unable to get a duck to stay still long enough). I occasionally use a very fine and very soft sable brush. Absolutely don’t use anything except a super fine sable. Many brushes will be too harsh and you will risk scratching the screen.
Assuming dirt which can’t be removed with blowing or gentle brushing– put the screen under a cold water tap, hold it only by its edges as even finger pressure can cause the matt side of the screen to deform and this will create dull spots in the view. Use cold water only and don’t use excessive pressure from the tap.

Don’t rub or press on a focus screen. Dry with you cold air rocket blower – using distilled water as a final finish before blowing dry will give a nice look and avoid any streaks as the water contains no impurities.

By the way distilled water without impurities is ABSOLUTELY DISGUSTING to drink – don’t let marketing idiots tell you that their Pura Hydro 100% water is amazing because any 100% pure water is HORRIBLE to drink. It’s the impurities like dissolved salts that make water taste acceptable.
If the cold-water approach didn’t work here’s the final answer…

Apply a blob of low Ph dishwashing liquid to the screen. Agitate the blob with your fingers which have been pre-softened in hot soapy water. The trick is to let your fingers ride on top of the blob as you roll the blob of liquid around on the screen. Your fingers don’t touch the screen they ride on the blob like a hovercraft. Flush off with cold water and then distilled water and blow clean with a cold air blower.

I use this as it’s a similar approach to cleaning telescope mirrors which are even more fragile than focus screens – they can’t even have low Ph dishwashing liquid and have to be done with pure soap suds which really is a pain. Before I did camera repair I did astronomy equipment repair and telescope mirrors and lenses are figured to wavelengths of light and a fair bit tougher to deal with than most focus screens.

How to clean a focus screen: Focus screen cleaning with water

TWO PART FOCUS SCREENS

For screens with a two-part construction there are additional issues. You can’t put them under a cold water tap as water will leak into the air gap between the screens. Normally that’s not an issue as you will only need to blow the top and bottom of the screen with a blower brush. Normally the screens are fitted into a carrier. If stuff has gotten between the Fresnel and the condenser it’s down to the way the screen was manufactured as to how to manage it.

A Minolta SRT is relatively simple and the screen is composed of a Fresnel and condenser held together with teeny screws and spacers. Unfortunately to fully remove an SRT screen you need to disassemble a large part of the camera.
However very often the dirt is only on the top surface and removing the prism of a Minolta SRT or Canon FTb is relatively easy though not advised for the beginner. Be very careful when you manage this because the meter needles and followers are VERY fragile.

Minolta SRT Focus Screen Assembly — A Minolta SRT focus screen assembly. To dis-assemble the screen requires a large amount of work as much of the cameras internal parts have to be removed.

2 part focus screen — Anatomy of a two part focus screen – in practice they can be harder to strip down.

Canon FTb Focus Screen — Canon FTb – A camera with a two part screen and its even harder to deal with than the Minolta SRT.

A Nikon F has an easily removable two parts screen which is mounted in a carrier and is relatively easy to dis-assemble but very often the two screens are bonded by a thin tape. The tape has glue on it and of course the glue can decompose and leak into the gap between the screens. It’s a nasty situation. To be fair I have only seen this once or twice. If that’s you – then you are out of luck because I have yet to find a way to fix that and suspect there’s nothing much to be done except pay a scalper on eBay for a replacement screen. The Nikon F, F2 and the Canon F1 all have two part screens but they are easily removable and will only usually need a blow or brush. It’s rare to have to separate the screens.

If you do have to go as far as screen separation NEVER mess with the condenser screen- its usually a very soft acrylic and will scuff and scratch easily. Use cold water only, breathe on it and VERY GENTLY wipe with a cotton bud.
The Fresnel can be treated as per the single part screen cleaning already described. BUT – and in tales of derring do like fixing a focus screen there is ALWAYS a but…

Getting a screen back together without any dust creeping in can be exhausting. Originally these were factory assembled and although they weren’t done in a clean room by todays standards they were assembled by very sharp assembly line workers – how they did it is a mystery (witchcraft I suspect). You need a clean environment, a blower brush and the patience of Job will not suffice – you need the combined patience of every Saint in heaven….. but, it can be done.

Thankfully most two part screens almost never need to come apart.

To check you got the screen dust free use a jewellers loupe and a good light – at a pinch the eyepiece from the viewfinder will work if it’s removable without too much fuss. Remember the eyepiece of the viewfinder is a magnifying glass so any imperfection in the screen will be more visible in the camera through the viewfinder than to your naked eyeballs.

FINALLY

Final cautionary note – I periodically see people suggesting putting some low tack tape on the screen. It’s a bad idea generally to clean a focus screen this way because the Fresnel side is very finely cut and as already stated you can flatten the grooves with not much effort. The low tack tape idea though can work in extreme situations but it’s really the thing to use when nothing else has worked and it’s that or the power of prayer.

If you have had to remove a prism to get to the top of the screen you may as well clean the prism surfaces as dust, if its on the top of the focus screen, will usually be on the prism as well.

The prism shouldn’t need much cleaning usually – at most breathe and a microfibre cloth or a soft cotton bud. I use a superfine cloth from Baader Optics. If it has glue residue from decaying light seals I use a very dilute Isopropyl solution.

As with the focus screen Don’t rub the prism it can scuff easily in most cameras – it’s a very finely ground bit of glass and needs careful handling.

For cameras with easily removable screens when the screen comes out you will have access to the base of the prism and you can clean using just breath and a cotton bud but be very gentle.
So now you know how to clean a focus screen.

Minolta SRT focus screen before cleaning — It can be done – this is the view through a viewfinder of a Minolta SRT before cleaning…

Minolta focus screen AFTER cleaning — …And this is what it looked like after cleaning.

Minolta MD Rokkor 45mm f2 Lens Repair Guide

A step by step repair and servicing guide for the much loved Minolta MD Rokkor 45mm f2.

The MD Rokkor 45mm f2 lens was, believe it or not, a low cost budget lens that Minolta primarily fitted to the budget XG series of cameras. The lens has now become something of a hyped up item thanks to people adapting them for digital. In actual practice they are solid if unremarkable lens for most film users.
Some people find the 45mm focal length more useful than a standard 50mm and the lens is very compact being almost a pancake design but personally I am not a fan of this lens.

Unfortunately, like many MD series lenses the 45mm f2 can suffer haze issues caused by vaporising oil from its helicoils. Very often the focus feel is either over firm, very loose or gritty. These conditions are almost always a sure sign of lubricants vaporising over time. On the plus side its very rare to ever see an MD series lens with the dreaded oiled up aperture diaphragm.

Copyright 2022 High5Cameras,
Free to use, copy and distribute so long as no charge is made for use,
distribution or access and authorship and web address is freely acknowledged.

Most Minolta MD series lenses are very simple to service and there is a general guide for the 50mm versions here. Most MD’s are very tolerant and kind to beginners. This is not the case with the 45mm which can be very fussy with respect to its focusing helicoils.

You will need some small containers for screws. I use ice cube trays for my work and use a sharpie pen to scribble as to which screws are in which cell of the container.

The lens used for this guide was in very poor overall condition with a very stiff focus feel and extreme haze. In addition the rubber grip had vulcanised badly and no amount of chemicals or heat would ever have returned it to the correct size for the focus barrel. In the pictures you can se just how much dirt and general muck there was in the lens at the start. -this is quite typical for MD lenses sold online.

Read through the whole guide before starting so you know what you are doing and always be mindful of what you are doing when you start work. The most common beginner mistake is to press down on the lens and forget that the opposite side is exposed, this can lead to snapped off aperture levers or wrecked front optics. Keep the lens capped on the opposite side to the side you are working. Work slowly and carefully and dont rush. There are no Olympic sports involving the fastest lens rebuild and a rushed job will lead to mistakes.

Relax, have fun and take your time.

You will need the following tools and parts to carry out repair and servicing of the MD Rokkor 45mm f2

Minolta MD Rokkor 45mm f2 Repair Guide – Disassembly

First step is to remove the beauty ring. On most short focal length MD series this is best done with a rubber cone.

The beauty ring does have spanner slots for a lens spanner but its best to avoid using a lens spanner if at all possible as the beauty ring is a relatively soft plastic which can be disfigured easily.

You can see the focus ring rubber grip is missing as the grip was so badly out of shape it would just fall off the lens. I’ll show you how to deal with that later.

As you work on the front of the lens remember to keep the back of the lens capped to avoid damage.

Remove the filter ring. This is secured with three small screws. Use a JIS driver here to avoid damage to the screws heads.

Now remove the three JIS screws that secure the front element group.

You can see the general poor state of the lens here with accumulated muck and dirt hiding behind the beauty ring.

The front element group can now be lifted off. Store this somewhere safe. Don’t bother cleaning it just yet.

You may end up having to do a partial rebuild so leave cleaning the glass until everything else is ready.

Note: This lens can suffer very badly from oil vapour and you may find the front optical unit is stuck due to suction. Use a cocktail stick to create a small gap between the optical units surround and the lens body.

The MD Rokkor 45mm f2 - Removing the focus barrel

Remove the three screws around the edge of the focus barrel. The barrel will then simply lift off the lens. Before you do this double check the lens is still at infinity focus.

You will find the focus barrel is a two part piece. The main plastic barrel with its rubber grip and a metal insert. These can be separated easily for cleaning. The metal insert is often stuck down by accumulated dirt and oil.

The MD Rokkor 45mm f2 - Measuring the helicoils

With the focus barrel removed you need to measure the gap between the helicoils.

The outer helicoil has a lip running round it and I usually measure the gap using a selection of jewellers drivers. When the tip of the driver is a good fit into the gap thats a fix on how the helicoil needs setting on reassembly. It’s super critical to get this right with the 45mm f2. If you don’t theres an excellent chance that on reassembly you will need too much back focus on one of the helicoils and cause the diaphragm to jam.

The helicoil gaps are circa – OUTER=1.5mm – INNER=2.5mm

The MD Rokkor 45mm f2 - Marking the helicoils

Next job is to mark the helicoils at their infinity focus point. I use a scriber to put a small scratch into the helicoil rings. Heres the outer helicoil marked with respect to the focus index mark.

The inner helicoil is also marked for infinity with respect to the focus index mark.

It’s good practice to mark these and also mark the point at which the helicoils separate later on. On this lens so long as you obtained good measurements earlier of the helicoil distances and you have marked the alignment points you can skip marking the helicoil thread entry points.

The lens is quite simple and there will only be a very limited number of options where the helicoils align. Its relatively simple if you don’t get the correct entry point for the threads to see its wrong. You’ll see why later on.

The 45mm Rokkor - Removing the lens mount

It’s now time to turn the lens over and start work on the rear of the lens.

Remove the 4x JIS screws on the mounting plate.

The lens mount will now simply pull free. Be careful not to remove the the aperture control ring. It has a small spring and ball bearing which can fly off and get lost.

On the 45mm f2 MD Rokkor the ball bearing and spring are located on the top of the lens near the f stop index markings. This makes it quite easy to handle for reassembly.

You can see the small detents that the bearing clicks into just to the left of the arrow.

You can also see more dirt and mess inside the lens. This is fairly typical for most MDs.

Cup the rear of the lens with its aperture in your hand and pull the body of the lens away to seperate the aperture ring. Immediately examine your hands and the lens to locate the bearing. It will sometimes fly off and its very tiny at 1.2mm and easily lost.

If you are nervous about this bit then use a large Tupperware box or a bucket to put your hands in while you separate the aperture ring.

Note this pic was from an earlier lens which looks a little different.

On this lens the oil contamination was so bad that the helicoil lubricant had turned into something like mud which stuck a lot of parts together. As a result the aperture ring ball bearing stayed with the ring. You can get an idea how small this is (1.2mm) here it is against a toothpick.

And here is the tiny spring which forces the bearing into the aperture click stop detents.

I tease this out with a cocktail stick – the bearing and spring are stored in an old film container until needed during reaasembly.

It’s safer to remove the spring to reduce any risk of loss while cleaning the lens parts.

MD Rokkor 45mm f2 - Removing the rear optical unit

We can now remove the rear optical unit. On most MDs you would take this out earlier but the 45mm is slightly different. It is wiser to leave it in place until the aperture ring has been dealt with.

Remove the three JIS screws that retain the plate surrounding the rear optical unit.

Note how the plate has a cut out for the aperture control lever.

Remove the plate.

The rear optical unit can now be removed. Store this safely.

Do not clean it yet – it’s best to leave the optical surfaces to last to reduce the amount of cleaning they are subjected to.

Removing the focus lock tab from the MD Rokkor 45mm

The focus lock tab can now be removed. If you are going to hit trouble with an MD lens this is where it will be. These screws were often glued into place by the factory.
You absolutely need the correct sized JUS screwdriver for these or you will round the heads off.

If the lock tab screws don’t shift easily use a soldering iron to heat the screw head. Once the screw head is hot the glue should give way. Be careful while doing this as the lens is mostly plastic which will melt.

With no lock tab securing the helicoils you can now simply unscrew the inner and outer helicoils from the lens body.

Here is the outer helicoil (silver) and the inner (black) helicoil separated.

The inner helicoil contains the diaphragm mechanism so needs to be handled with extreme care during cleaning.

On this lens the lubricant had turned into something like tar and it was an awful job to get it clean.

The main parts of the Minolta MD Rokkor 45mm f2

With the lens almost completely stripped you can now clean all of the lens body work.
Note that the rear element group, diaphragm and inner helicoil are all one piece. You are advised not to take this to pieces.

To clean the inner helicoil with it’s built its diaphragm I use cotton wool balls to take off the worst of the mess on the threads and then use a cotton wool ball dampened with Isoprop to slowly work away the rest of the mess. Once its dry I use a a soft old tooth brush to clean away any remains. You need to be very careful then mess does not get into the diaphragm mechanism so work very slowly and methodically with this piece.

The diaphragm of the MD series almost never gums up so it is rare you would ever need to take this part and I don’t recommend stripping it down for fun.

The rest of the lens body parts can be cleaned with Isoprop or hot water and a mild detergent. When I service a lens EVERYTHING gets cleaned. For final finishing I flush all parts BUT NOT THE INNER HELICOIL AND DIAPHRAGM under cold water and then blow dry.

Be very careful when cleaning the lens mount part as it contains springs and levers. I use Isoprop and a soft toothbrush for this.

The helicoils and lens body thread for the outer helicoil are then chased out with cocktail sticks to ensure that all thread surfaces are free of dirt and contaminants. Finally make sure the helicoils are running smoothly without lubricants to assess if any threads are damaged. Very often people have seen You Tube videos and poured lighter fuel in the lens to get the focus moving. This is a fast fix but creates long term issues with excessive thread wear and as a result you may need extreme measures like a lapping compound to polish out any defects in the threads.

Repairing the rubber grip on the 45mm f2 MD Rokkor

On this lens the rubber grip was in a terrible shape. It was so loose that if you tipped the lens nose down the grip would simply fall off.

Sometimes it is possible to reattach a slightly loose grip with double sided tape or use boiling water to shrink the grip. Some people swear by a soak in Naptha. These fixes will work if a grip is slightly loose but in this case there was no magic solution to shrink the grip by around 1/4 inch. Plus the grip had flattened out in its width so would not easily fit the focus barrel cut out for it.

The radical fix was to cut three of the diamond patterns out to reduce the grips circumference. I went slowly cutting one section at a time until the fit was suitably tight.

Once the fit was ok the barrel and rubber grip were cleaned and I used Evo-Stick Serious Glue to reapply the grip stretching it into place. Normally I would use a contact adhesive but I wanted time to make sure I could stretch the rubber into place and securely clamp it.

After the glue had set fully the grip was cleaned with a nice gritty toothpaste and soft toothbrush. Toothpaste can do wonders for rubber. The grittiness in it removes dirt and the oxidised layer and the menthol oil helps to rejuvenate the rubber.

The join was placed on the base of the lens to make it inconspicuous but in truth unless you knew the join was there and where to look you’d never see it after this repair.

Minolta MD Rokkor 45mm f2 Repair Guide – Reassembly

First lubricate the helicoils. I usually use Helimax XP for Minolta MD series as it provides a perfect damping while retaining a good feel. It’s also able to work at both high and low temperatures and resists migration.
The outer metal helicoil needs only a light coating while the inner helicoils needs a slightly thicker dose. Getting the feel right is a bit of witchcraft and comes with experience so you will need to experiment to get the feel right.

The name of the game is to get the helicoils at the same distances from each other and the body as you measured earlier and also aligned with the marks you made PLUS…

…making sure that with the distances set correctly and aligned with the marks you made before disassembly the focus tab fitting is in the right position.

The inner helicoil has to align with the focus tab position with the measurements and the marks.

Note: In this picture the assembly had progressed a bit and the aperture ring and rear optical block has been installed.

A quick test of whether things are close with regards to the helicoils is to drop the focus barrel on to the lens at this point and place the filter ring on top. If its set right the filter ring outer edge will sit just below the top of the focus ring.

Once the front optics unit is installed the edge of the filter ring will be almost level with the edge of the focus barrel when the lens is at infinity.

Note: In this picture the aperture ring is back in place – this is just to show the relationship between the filter ring and the focus barrel.

Replace the small spring in the aperture ring

Replace the small spring back into the aperture ring if it was removed earlier.
Apply a small blob of lithium grease (Helimax XP will do) onto the top of the spring and apply the ball bearing. The grease will hold the bearing in place. Apply a small smear of grease to the detents on the lens body. This will give the aperture ring a smooth feel.

Before doing this establish how the aperture ring fits to the body. Different Rokkors and MD have differing fits. The 45mm is relatively easy as the bearing and the index marks are in more or less the same place at the top of the lens but some Minolta lenses will only allow the aperture ring to mount in one location – on the 45mm f2 Rokkor the best orientation is with the aperture ring set around the f5.6 mark.

This is the tough bit, especially for a beginner. You need to get the ball bearing trapped into position. Apply the aperture ring at a slight angle to the body to trap the ball bearing and then push the rest of the aperture ring down and into place. You may need a small amount of pressure to do this but go careful. The aperture ring is plastic and can break if you apply too much force.

Once in place test the aperture ring by rotating it to make sure it is clicking nicely in place.

Use a bucket or large Tupperware box to do this part in to minimise the risk of losing the tiny bearing.

Give the rear element a clean. Normally I use just breath and a lint free cloth but if the lens is particularly hazed from oil I use a dilute Isoprop solution applied with a lint free cloth and then breath and the lint free cloth.

Replace the rear optical unit and its surround taking care to make sure the cut out in the surround is aligned with the aperture lever.

Take care as you work that the aperture ring stays in place. If it comes off you risk losing the small bearing.

Replace the rear optical unit screws.

Replacing the lens mount on the 45mm f2 rokkor

Replace the lens mount making sure that the cut out in the lens mount aperture lever ‘captures’ the aperture lever on the diaphragm assembly.

Set the aperture ring to f16 and rotate the lens mount until the diaphragm closes down and the the screw holes align with the threads on the lens body.

Replace the lens mount screws and check diaphragm is operating normally across the range of the aperture ring. At f2 the aperture blades should just clear the edge of the diaphragm. Check aperture blades are moving move with each click stop on the aperture ring.

Once happy put the rear lens cap on and turn the lens over. It’s time to assemble the front elements of the lens.

Replacing the front element of the Rokkor 45mm f2

Replace the front optical unit after suitable cleaning. I use a mild Isoprop solution and then breath with a microfibre cloth and a final blow out with a rocket blower.

Replace the three screws that retain the front optical unit.

Normally I use a collimator to set the lens at infinity but as these are hard to come by the alternate method is to mount the lens on a known good camera. Use the silver ring showing on the lens to focus.

Setting infinity focus on the Rokkor 45mm f2

Focus on a distant object. I use some radio towers which are around 8 miles away. If all is well the lens should come to focus easily.

Once the lens is focused at infinity check that the aperture is working correctly both for automatic stop down with the camera and by manually turning the aperture ring. The 45mm F2 is unforgiving and if the focus is set too far back it will jam the aperture. It has a very narrow range over which it will come to infinity focus without causing aperture jams which is why its critical to get the distances on the helicoils as close as possible.
DO NOT MESS ABOUT BY WINDING THE FOCUS OUT!
You can cause the inner helicoil to disengage from its lock tab.

With the lens at infinity replace the focus barrel so that the infinity mark is aligned with the lens index mark.

Replace the focus barrel retaining ring. Make sure it lines up with the threaded holes beneath.

Refit the screws but do not over-tighten. They will shear quite easily. Tighten no more than the pressure you can apply but having the screw driver handle between thumb and forefinger.

Check lens is fully working. Check that focus throw runs smoothly from infinity to minimum distance and that the lens is focused at infinity. Check the aperture is working correctly.

Replace the filter ring and secure with its retaining screws.

Minolta used differing filter rings – some have cuts out that go over the front optical unit retaining screws. Some have holes and some have tabs that stick out with holes in them.

Replace the beauty ring.

If all has gone well then give yourself a well deserved cup of tea some hearty self congratulation and enjoy the lens.

The lens used in this guide will be sold in our online store in due course.

This Nikon 50mm Repair Guide article can always be improved. If you have any questions and or comments we would love to hear them below. Mel.

Nikon 50mm Repair Guide f1.8 AiS

A step by step Nikon 50mm Repair Guide f1.8 AiS with notes on managing the Series E version of the lens.

Copyright 2022 High5Cameras,
Free to use, copy and distribute so long as no charge is made for use,
distribution or access and authorship and web address is freely acknowledged.

The Nikon 50mm f1.8 AiS lens is almost identical to the late model Series E lens. Some of its cosmetics are slightly different but it uses almost identical construction. I have made notes through this guide to point out any major differences between the AiS and the Series ‘E’ version so this guide will help you manage either version.

Nikon 50mm f1.8 E series and AiS — Series E to the left, AiS to the right. The AiS is slightly longer. Lens construction is almost identical.

Nikon 50mm E Series and AiS — The AiS has slightly better coatings but either lens will return very sharp results.

You can see from the images above the second version 50mm f1.8 Series ‘E’ and the AiS version appear almost identical. The cosmetic difference is basically the focus barrel is slightly longer on the AiS with a slightly different grip pattern and the aperture control ring is also slightly longer with a bigger separation between the F stop markings on the lens and the repeater markings for the cameras Judas Window for aperture display in the viewfinder.

The Series E was a low cost version of the AiS for Nikons consumer cameras. The AiS version has better coatings but either lens will return superbly sharp results.

When new and in production the Series E was significantly cheaper than the AiS but internet hype has promoted the Series E version to such an extent that its now almost the same price as the AiS version on the used market.

Nikon 50mm Repair Guide – NOTES BEFORE YOU START

The Nikon AiS 50mm f1.8 is a bit of a challenge. It’s nowhere near as tough as some lenses but it does have some booby traps to catch the unwary.

If you have read my guides on Minolta lenses you will know that Minoltas are usually very kind to beginners and you can afford to not worry too much about helicoil distances. That’s absolutely NOT true with this lens and you need to mark alignment points on EVERYTHING unless you want to spend the next 2 weekends reworking it!

The lens used for this Nikon 50mm Repair Guide was not in a good state. Focus was very stiff due to the oils evaporating inside the lens. This had led to haze on the glass and a very stiff focus. This is very common with these lenses especially if bought off places like eBay where sellers are generally clueless. The Series E that was done in tandem with this lens was even worse with a flakey aperture control, hazed glass and almost no lubricants left on the helicoils giving the lens a sloppy and rattly feel.

Nikon 50mm Repair Guide – NOTES ON WORKING WITH THESE LENSES

Nikon are swinish at applying threadlock so an absolute must for this lens (and any others to be honest) is a decent set of JIS screwdrivers. Philips drivers can be totally relied on to round out screw heads on most Japanese gear and it’s a near certain result when working with Nikon lenses. If you hit a stuck screw apply some Isoprop or Acetone and wait, if its still stuck apply a bit more and wait. Last resort is heat as you will see with this lens. Brute force is seldom a good thing with this lens.

You can use acetone sparingly but be VERY CAREFUL – the lens is mostly plastic and acetone can melt the lens parts as well as the threadlock.

Remember – There is no such thing as luck in repairing optical equipment, if you do it right, using skill and patience you will be rewarded with a perfectly operating lens. A rushed or bodged job will result in the lens being devalued, unpleasant to use and possibly unusable so…..take your time, get the right tools and materials, don’t take shortcuts or advice from people who know less than you (check out my camera history here).

The biggest issue with the 50mm f1.8 AiS is the very tricky focus helicoil distances. I have made lots of notes throughout the this Nikon 50mm Repair Guide so make sure you read the entire guide before starting work.

You will need the following tools and parts to action this Guide

Nikon 50mm Repair Guide f1.8 AiS – Disassembly

Nikon 50mm Repair Guide - Removing or replacing the beauty ring from a Nikon AiS

First step is to remove the beauty ring. On the 50mm AiS this is relatively straightforward with a rubber cone.

On the ‘E’ Series 50mm f1.8 these are very thin and very fragile. Too much pressure will cause the ring to distort outwards and jam.
If the beauty ring is stuck apply some Isoprop and wait. You may need repeated applications.

Nikon 50mm Repair Guide - Nikon AiS and E Series front fittings

With the beauty ring removed this reveals the filter ring and front lens groups retainers. Note the filter ring screws sit on top of the filter ring while the cut outs sit over the front optic retaining screws.

On some Series E versions the lens retainers are countersunk underneath the filter ring so you will only see the filter ring screws.

Nikon 50mm Repair Guide - The filter ring screws on the Nikon AiS and E series 50mm Lens

First remove the filter ring. This is secured with three small screws. Use a JIS driver here to avoid damage to the screws heads.

Nikon 50mm Repair Guide - The front element retaining screws

Now remove the three JIS screws that secure the front element group.

Nikon 50mm Repair Guide - Removing the front elements group on the Nikon AiS and E Series

The front element group can now be lifted off. Store this somewhere safe. Don’t bother cleaning it just yet. This lens can be a pig and you may end up doing multiple rebuilds.

Nikon 50mm Repair Guide - Nikon Ais showing oil contamination

This lens had very severe oil contamination. You can see the oil is present on the front lens group mounting plate and on the top of the focus helicoil. This is a typical issue. The internal glass has also hazed badly from oil vapour.

Nikon 50mm Repair Guide - Nikon AiS focus barrel retainers

Now remove the focus barrel. This is retained by a thin metal retainer.

Before you remove this set the lens to infinity.

Nikon 50mm Repair Guide - Nikon AiS focus barrel issues

Note the relationship between the focus barrel retainer screws (RED CIRCLE) and the inner helicoil lobes (YELLOW ARROW).

These are critical on reassembly. Failure to get the relationship right will mean the lens focus will jam as you move towards back towards infinity as the lobes will catch on the focus barrel retainer ring.
Note the aperture control spring – this is discussed later in the guide – you need not worry about this if it is secured to its fittings.

Nikon 50mm Repair Guide - Nikon AiS and E Series 50mm focus barrel

And now the focus barrel can be removed together with its inner metal retaining ring. The retaining ring can be removed for cleaning but it is a very thin piece of metal so needs to be handled with care.

Nikon 50mm Repair Guide - Measuring helicoil gaps — Measuring helicoil gaps

With the lens at infinity measure the distances between the helicoils (I usually use some very fine jewellers drivers to get an estimate of the width between the helicoils) and also put a mark on each helicoil and one on the lens body so you know where the zero point is for infinity….

This pic was taken a bit later in the process but it gives you an idea where you are marking

Nikon 50mm Repair Guide - The Nikon 50mm AiS mount ring

It’s now time to turn the lens over and start work on the rear of the lens.

Remove the three JIS screws using a JIS screwdriver. These screws are usually VERY tight. Nikon loved the use of thread locker so if they don’t turn out easily apply some Isoprop and wait. A JIS driver is essential for these as they can be rounded out very easily.

The mount screws on this lens were particularly troublesome so I had to resort to extremes.

What you see here is the core of a high powered soldering iron (30W) applied to the screw heads. You need to do this until they are too hot to touch. This will melt the thread locker but you need to be VERY careful as the aperture ring is plastic. Mindfulness at all times!

With the three screws removed the lens mount can be simply lifted off.

Note that the aperture lever on the mount engages with a slot on the lens body.

From this point on the lens must be supported by a cap at the rear as otherwise the rear optics will be in contact with any surface.

Take note of the orientation between the aperture lever (YELLOW) and the aperture slot for the mount (RED).

This is one of the less amusing aspects of this lens. The two aperture controls have to be aligned on reassembly together with the lock tabs AND the helicoils.

Lift the aperture ring off. Unlike many lenses there is no small bearing or spring to worry about.

Put a mark on the lens body where the black index mark is on the silver coloured ring. This should also be the mark you made for the focus at infinity

This will help you orientate it later when replacing it and also will help you reorientate the lens for mounting if you are forced to do a partial rebuild to get the infinity focus right.
You can see here a mark has been made both on the lens body and the helicoils for infinity focus.

Remove the three screws around the silver index collar.

Remove the silver index collar.

Remove the focus lock tabs. There are two. One on either side.

These screws can be VERY tight and bonded with thread lock. Be careful with acetone or heat here as most of the core of the lens is plastic.

The two helicoils can now be unscrewed.

With this lens it is really critical to have these marked for infinity and also a mark where the helicoil separates so you know where the thread entry point is. It is well worth reading Richard Haws guide on working with helicoils HERE.

This is a shot from an earlier guide on the 1st generation Series E guide and shows the inner helicoil separation.

I didn’t get a shot of this lens but they look almost identical anyway.

And here’s the outer helicoil being removed from the lens body from the earlier guide. The lens body to the right is a little different but the basic principle is identical.

Nikon AiS 50mm f1.8 stripped down — Nikon 50mm Repair Guide – All Parts

If you have fungus in the rear groups you can use acetone very sparingly to remove the rear group retainer but be very careful about spacers. You will also need a lens sucker to extract these and replace them. If the fungus is between lenses in the front group it’s a write off. The front group is a sealed group and cannot be disassembled.

The optics on this lens were ok and just needed the outer and inner facing glass to be cleaned. To remove oil I use a dilute Isoprop solution – 50/50 with water plus breath and a microfibre cloth.

Once fully cleaned the helicoils are lubricated with Helimax XP. As with most lenses you need to get the dosing right for the helicoil lubricant. Like many plastic bodies lenses this one needed a very tiny amount of lubricant on its outer helicoil metal/metal threads but a thicker dose on the metal/plastic threads.

The core of the lens contains the rear optics. Cleaning the old grease off of these is a careful job as this part contains the rear optics and the diaphragm. I normally use cotton wool balls to remove as much of the old lubricant as possible and then apply a dry toothbrush to get the remains of the old lubricants out of the threaded parts and then use more cotton wool balls. Once its close to clean I use a very lightly moistened cotton ball with some Isoprop to make sure its fully clean. You have to be VERY careful with this.

The other threads are cleaned out with alternate doses of hot soapy water and Isoprop and finally all threads are chased out with a cocktail stick to make sure the are completely free of contaminants like old dried lubricant.

All metal and plastic parts, with the exception of the lens core, are thoroughly cleaned of lubricants that had leaked. This includes the front face of the inner helicoil, the focus barrel and the mounting parts of the front optical assembly.

Do not clean the front optical unit inner surface until you are ready for final reassembly – you will see in the reassembly phase you may have to remove this a few times while setting the lens up so don’t clean its inner surface until you are sure all is working well.

Nikon 50mm Repair Guide f1.8 AiS – Reassembly

When reassembling do not over-tighten any screws. This lens can be a pig and you may end up disassembling. The name of the game is lightly tighten stuff down. Test the lens and if all is well go back and retighten screws after you are sure all is working well.

First lubricate lightly the outer helicoil and rethread it to the lens body. Assuming you marked the lens up appropriately earlier you need to find the thread entry point that allows the same distance to be achieved between the helicoil and the lens body AND the marks you made to align at infinity.

Now insert the inner helicoil using the same approach. The outer helicoils inner face has been given some lubricant but a bit extra is added to the threads on the inner helicoil.
Thread the inner helicoil into the outer helicoil using the marks you made to find the thread entry points and that the distance is the same as when you took it apart and the marks you made earlier align.

Like the Series E the AiS version is no fun. Nikon designers could be cruel! As well as the helicoil distances you have to meet the following as well.

The inner helicoil must align with the lock tab positions and…..

….The relationship of the aperture lever must be as pictured. The aperture lever has to be to aligned so that the lever is at the 6 o clock position while the mount aperture connector is at the 3-c-clock position and…

(Note this pic was taken a bit later – its only to show the relative positions of the aperture, lock tabs and detent slots for the aperture control ring.)

…The detents for the aperture ring are also in the right position alongside the aperture lever on the lens body. It’s not as hard as it sounds but you need to be aware of this now before you commence reassembly. Apply a light smear of lubricant to the detents – just a small smudge is enough.

Once you are happy that all is well and alignment of the interior parts is correct and the helicoil distances are in close approximation to what you measured before disassembly you can replace the focus lock tabs. Do not over-tighten just yet- you may need to make changes later.

Replace the silver ring using the mark you made earlier and replace the three screws.

If for any reason you couldn’t or didn’t mark the helicoils for infinity its best to leave this ring off for now and come back and add it later. Without this ring it’s much easier to grip on the outer focusing helicoil when testing. The mark on the lens body will help you sort out orientating the lens to the camera mount.

Replace the aperture control ring making sure it goes OVER the aperture lever on the lens body.

It needs to be put on by placing it vertically downwards NOT from the side.

Replace the mounting ring making sure the aperture lever on the mount ring locates into the slot on the lens body.

Replace the front optical unit after suitable cleaning. I use a mild Isoprop solution and then breath with a microfibre cloth and a final blow out with a rocket blower.

Note the fittings on the optical unit carrier. The holes are for the lens retaining screws while the slots are for the filter ring.

Replace the three screws that retain the front optic.

Note the brass outer helicoil…..

You can now mount the lens as it is on a known camera and using the brass outer helicoil get focus on a distant object. I usually use two radio towers which are around 8 miles distant. I can use a collimator but this only works well if you have a reference lens.

Heres the lens mounted on a trusted and reliable F-301.
The focus barrel is now placed over the lens with the infinity mark aligned to the index mark and lightly secured with its three screws for a final test.

If testing is good and the lens operates freely from end to end of focus throw the focus barrel can be secured.

Bear in mind a lot of this lens is plastic so don’t go mad on tightening stuff. Safest method is to use the small JIS driver between thumb and forefinger and tighten using just your thumb and forefinger. When it feels tight thats tight enough.

If the focus jams then chances are you have not enough space underneath the lobes of the inner helicoil OR positioning is in some other way incorrect. In which case your only option is to rebuild.

If for any reason you were unable to make markings for thread entry points or infinity focus you may end up reworking the lens. I have had one where the focus was jammed so it was not possible to get useful markings.

The filter ring screws on the Nikon AiS and E series 50mm Lens

With the focus barrel on you now only need to add the filter ring and…

Replace the beauty ring using a rubber cup.

Notes on the Aperture Control Spring

You will have seen earlier that the aperture mechanism uses a spring on the front face of the diaphragm BUT… the real power in the aperture control is the spring located in the mount assembly. If you have a very slack diaphragm the chances are it’s the spring in the mounting plate. On the inside of the lens mounting plate you can see a small spring is hooked over the hole near the aperture lever. This can come free if while cleaning you have dislodged it.

To reconnect the spring you need to remove the three recessed screws around the edge of the mount plate. Ignore the screw that stands proud of the rim and just remove the three recessed screws.

With a little bit of wriggle the inner black part of the mounting will come free allowing you access to the spring. When replacing be aware of the slot that allows the camera side aperture lever to move.

Here’s the spring with its fixing. It’s end simply loops into the hole.

DO NOT remove the screws on the aperture lever – these are fine tuned by the factory for the aperture and are very much best left alone.

Mount the lens for a final check, check infinity and focus throw and also make sure the lens stop down is working correctly.

Thats it – I will wish you all the best of luck with this lens – it can be a complete perisher.

It is a superb lens when clean and operating well and I hope this guide will have allowed you to return this lens to pristine condition.

This Nikon 50mm Repair Guide article can always be improved. If you have any questions and or comments we would love to hear them below. Mel.

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Further Reading

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Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Focus Helicoils

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Lens Sleeve

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Optical/Diaphragm Assembly

Nikkor-Q 135mm f3.5 NAI Lens – Replacing the Focus Ring and Lens Mount

Nikkor-Q 135mm f3.5 NAI Lens – Outcome

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Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Aperture Ring Assembly

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Focus Helicoils

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Rear Optical Assembly

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Lens Mount, Sleeve and Filter Ring

Repair Nikkor-S 35mm f2.8 NAI Lens – Replacing the Front Optical Assembly and Focus Barrel

Nikkor-S 35mm f2.8 NAI Lens – Outcome

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Battery Leaks

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Minolta MC-X Rokkor PF 50mm f1.7 Repair Guide – Reassembly

Further Reading

WHY DOES A FOCUS SCREEN GET DIRTY?

HOW EASY IS IT TO CLEAN A FOCUS SCREEN?

TYPES OF FOCUS SCREENS

ISSUES WITH DIRT ON THE TOP SURFACE OF THE SCREEN

CLEANING A SINGLE PART SCREEN

CAUTIONARY NOTES HERE

TWO PART FOCUS SCREENS

FINALLY

Further Reading

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Nikon 50mm Repair Guide – NOTES ON WORKING WITH THESE LENSES

You will need the following tools and parts to action this Guide

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Nikon 50mm Repair Guide f1.8 AiS – Reassembly

Notes on the Aperture Control Spring

Further Reading