Posted on September 4, 2025July 8, 2026 by Mel — Leave a comment

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.

Starting serious photography back in 1972. Over the years she got to shoot film with most of the major brands in 35mm and large format as both a studio photographer and content provider for websites in the early life of the web. These days she is rediscovering photography and has become the GOTO person for knowledge on camera repair advice.

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

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

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..

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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.

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.

Nikon E Series Repair Guide

A step by step Nikon E Series Repair Guide to the first version of the Nikon Series E 50mm f1.8 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 Series E 50mm f1.8 started production in 1979 when Nikon launched the Series E line of compact, budget-conscious lenses.

The original Series E made between 1979 and 1981 was made almost entirely of plastic and its exterior finish is somewhat cruder giving it a budget look. The later version 2 made between 1981 and 1985 was a little larger and had a more refined look. Optically there’s little to choose between them.

The Series E line was comprised of eight lenses and was intentionally branded differently from the primo quality Nikkor lenses. Nikon obviously did not want the much vaunted Nikkor brand contaminated by lenses with plastic parts and lower quality coatings. Nikon being Nikon though just couldn’t do budget anything. They may have been low cost but Nikon managed to produce an exceptional lens in the 50mm f1.8 – the most common Series E lens.

The Series E 50mm was not originally intended to be budget but had its roots in Nikons requirement to improve their original 50mm f2 Nikkor. They gave this task to legendary Nikon designer Souichi Nakamura who somehow managed to create on a budget a lens with amazing properties. Small, light, almost pancake in appearance the Series E 50mm f1.8 could kick it with the best of them. It could blow more venerable lenses into the weeds back then.

Sadly its capabilities went largely unrecognised in its day. It was most usually bundled with Nikons low end consumer cameras like the EM and the FG which is why it lacks the ‘bunny ears’ of the more upmarket lenses designed to work with all of the pro gear as far back as the Nikon F. The EM and FG series cameras had a poor reputation for reliability and I suspect that pretty much doomed the Series E to obscurity. Pros never bought it anyway and consumers either lacked the skills to appreciate it or else found it stuck on a camera that was junked. The sole exception to this was the Nikon F-301, Nikons last manual focus 35mm SLR, which came bundled with a late model series E 50mm f1.8 early in production – the F301 found a lot of favour with pros, including me, as a backup camera.
It’s taken over 40 years for the lens to be truly appreciated. At one time a budget lens it now commands a fairly hefty price. Almost on a par with a Nikkor 50mm f1.8 in pricing!

The Series E has become a kind of must have among Nikon fans and digital users. Razor sharp optics and 40 years have finally given it the standing it deserves.

Nikon Series E 50mm f1.7 - Early and Late Versions — Nikon Series E 50mm – Late model on the left, early model on the right

NOTES BEFORE YOU START

The Nikon ‘E’ Series 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.

This Nikon E Series Repair Guide only covers the early version of the lens. If you want a good guide on the later version I can recommend Richard Haws guide here.

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 point on EVERYTHING unless you want to spend the next 2 weekends reworking it.

This particular lens was not in a good state and its focus barrel was jammed. As a result I had to work from scratch and estimate its helicoil distances. This resulted in numerous rebuilds. This guide will talk you through how to establish infinity focus if you have the same issues. If your lens is basically working AND you are very careful about marking and measuring the lens will be quite straightforward but its good practice to make marks and measurements. Get in the habit of doing that.

When working on one side of the lens (eg the front) always be mindful about what’s happening at the other side (eg the back). I always keep caps on as much as possible to prevent any accidents. The classic mistake is for people to press on the lens while it is on a workbench and break things on the back end of the lens like the aperture lever.

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 and wait, if its still stuck apply a bit more and wait. 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.

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 Series E lens is the very tricky focus helicoil distances. I have made lots of notes throughout the Nikon E Series Repair Guide so make sure you read the entire guide before starting work.

Nikon E Series Repair Guide – Disassembly

First step is to remove the beauty ring. 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. This one was stuck fast by layers of grime so it took a few applications of Isoprop soaked into the filter threads to get it to release.

Now it’s time to remove it with a rubber cup – do not apply pressure or the beauty ring will get distorted and will jam. If this isn’t working for you then you can try applying some sticky tape to the beauty ring and just try and turn it out with your fingers on the tape. Don’t let gum from the tape get on the lettering – the lettering can easily be damaged.

Here’s the beauty ring removed revealing all of the fittings and screws to get the front of the lens off.

First we remove the filter ring. This is secured with three small screws. Use a JIS driver here or the heads will round out.

Remove the filter ring.

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

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.

Now remove the focus barrel. This is retained by a thin metal retainer. It does not go all the way round the lens and is retained by three screws.

Before you remove this set the lens to infinity and mark the inside of the barrel for the two screws at each end. This will save a lot of grief later.

Here’s one of the screws being extracted.

And now the focus barrel can be removed – you can see in the picture the focus barrel retaining ring only goes around 2/3^rd of the barrel diameter and it’s position is super critical when replacing the barrel later on.

With the three screws removed the lens mount can be simply lifted off.
Note its orientation with respect to the aperture lever below.

Now you can simply lift the aperture ring away. Note how the fork on the aperture ring locates on the lens aperture lever inside.

Remove the focus lock tab. Again on this part Nikon loved to use thread locker so use a JIS driver only and if these are reluctant to come out apply a few dabs of Isoprop and wait.

Once the screws are out the lock tab can simply be extracted.

If you wish you can remove the aperture index ring.
When I rebuild I rebuild and everything gets cleaned.
You may HAVE to remove this to set infinity focus later so now is as good a time as any.
Note the orientation of the cut out with respect to the lens body and mark it appropriately.

Here you can see the index ring being removed and observe the cut out on the lens body. The reason for marking is I have seen this lens with an extra hole as though there were two positions. To avoid confusion just make a note or put a small mark on the lens body to indicate the orientation of the index ring.

This part is CRITICAL you need an accurate measurement of the distance between the inner helicoil seen here being removed AND a mark showing its position relative to the outer helicoil (the brass coloured helicoil in the picture) when they were at infinity focus. I normally use the tip of a jewellers screwdrivers to measure the distance by seeing which driver will fit in the gap between the helicoils.

If you cant measure because your lens was jammed don’t worry. I’ll show you how to resolve this but it’s a lot easier if its marked at inifinity.

This part is also CRITICAL make a measurement of the distance between the outer helicoil and the lens body and make a mark of how they were orientated with respect to each other.

Nikon E Series Repair Guide – Reassembly

Now insert the inner helicoil using the same approach. Thread the inner helicoil into the outer helicoil so that the distance is the same as when you took it apart and the marks you made earlier align.

If your lens was jammed like this one wind the inner helicoil in until it has around a 2mm gap between the inner helicoil and the outer helicoil.
The helicoils must also align with the focus lock tab position.
If you are assessing distance from an unknown start point (eg like this lens the lens was jammed) you MUST leave a cap of at least 1.5mm between the lip of the inner helicoil and the outer helicoil when the lens is at infinity. Otherwise you will be unable to mount the focus barrel retainer.

If the lens was marked up correctly you should find that the lock tab position will be very close to correct. Use the outer helicoil to get it exact.

If your lens wasn’t marked this is where the guesswork will come in. You will need to extract the inner helicoil and outer helicoils until you can find the sweet spot where the gaps between the helicoils are roughly right AND the lock tab position lines up.

Note: Do not tighten the lock tab down too much. If your focus is out at the end of the rebuild you will having to dismantle this part. The lock tab screws do not need to be thread popping tight.

POINT X (this will be explained later) If all of your threads have lined up and you are super confident the lens has been assembled exactly as it was when it was taken apart you can go ahead and refit the index ring.

My advice is to leave this ring out for the moment. This is one of the headaches with the ‘E’ Series 50mm f1.18. If you mount this ring and it turns out your infinity focus is off it will be harder to adjust the lens.

Replace the aperture ring making sure the forked connector is aligned to the lens body aperture lever.

Replace the lens mount making sure it is orientated correctly and the aperture lever is correctly located into its slot.

Replace the mount plate screws. Do not tighten these yet. Just dog them down until the lens mount is firm.

You need to make sure the lens can reach infinity focus at the end of the process. If it cant you will be taking this off again!

Replace the front optical element group and lightly screw down.

You need to make sure the lens can reach infinity focus. If it cant you will be taking this off again along with the mount place and aperture ring.

Mount the lens on a known good camera. This is tricky without the lens mounting index mark in place so be careful.
You will need to feel for the correct orientation to the mount. DON’T Force anything. Once the lens is in place turn the brass outer helicoil to reach infinity focus. I use a pair of radio towers about 8 miles away as a test of infinity. Find a distant object and focus the lens until the focus is sharp on the far object.

If focus is good at infinity you must make sure that the projections on the inner helicoil have at least 1.5mm gap between their lower edge and the top of the outer helicoil. Otherwise you will be unable to mount the focus barrel retainer.

If all is well and the lens reaches infinity AND you have a sufficient clerarance under the inner helicoil as per the previous note you now need to remove the mount plate and aperture ring and replace the index ring. Secure it using the small screw. Then replace the aperture ring and mount plate.

You can see in this picture with the index ring in place you only have a small amount of access to the brass outer helicoil for focusing but it is much harder to do the infinity test with this in place. This is why it was left off at POINT X

If you have not been able to achieve infinity and leave a sufficient gap under the inner helicoil you will need to disassemble and start the rebuild again. The Helicoils on the Series E lens are tricky to get right.

You will have to remove the front optical element to fit the focus barrel and its retainer. With the front element removed slip the focus barrel over the lens, check that the infinity mark is aligned to the index mark…

…and replace the focus barrel retainer.

Nikon E Series Repair Guide

SPECIAL NOTE:
If your lens, like this one could not be suitably measured for its original infinity focus this part can be a horror of a job. At infinity the focus barrel retainer may foul part of the lens. Your only option is to rebuild from the start again. You need to find an infinity position where the inner helicoil is a little bit further out which means the outer helicoil must move further in.
There is a sweet spot where this can happen but you may have to try several iterations to find it.
This is one of the less amusing aspects of the Nikon ‘E’ Series 50mm f1.8 early version.

Once you have found the sweet spot or, if your lucky and all has gone perfectly well on the first attempt, you can now do a final clean on the rear of the front lens if needed and then replace the front optical unit.

Replace the filter ring.

Replace the beauty ring. Be very careful with this and do not get it cross threaded. It can be very tricky to get it right as the beauty ring is so thin.

Final check and test of Nikon Series E 50mm

Mount the lens and run a final check on the lens, check infinity, check aperture and stop down.

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

What is Lens Fungus: – The Reason Why

What is Lens Fungus: – 2,400 Million years ago fungus developed. Long before most life on the planet and it’s been going ever since. These days if you’re an avid photographer with a penchant for classic lenses you’re most likely to discover it in a lens and will want to remove lens fungus quickly.

So, what is it? How does it get there? And, most importantly of all how do you remove lens fungus? It’s one of the questions that most often comes up on photography forums and message boards so to save me having to type this out repeatedly here’s an article that answers everything you ever wanted to know about fungus and how to get rid of it.

What is it? …Fungus is one of the earliest known life forms on the planet. Its spread by microscopic spores carried in the air. Right now you are surrounded by these spores, they are on your clothes, in your food and in the air you are breathing and both fungal spores and us get along pretty well. Many types of fungi are positively beneficial (penicillin for one, yeast for another). Many fungal types assist the breakdown of other organic matter but you didn’t come here for a biology lesson.

How does it get in your lens? …Well fungal spores are quite literally everywhere. When you focus a lens you are basically pulling in air, lenses are seldom sealed airtight and even if they were, on a vintage lens the spores would have been present in the factory, on the people assembling the lens and on the actual material in the lens. People more used to the modern world of microchips think in terms of clean rooms, sterile, devoid of any small motes. That’s not how classic lenses were assembled. The environment would have been more akin to a factory or, in some cases, a shed. So, the spores get in your lens. What happens next?

The spores are basically inert until they get good growing conditions. What fungi likes is dark and damp. And that’s why many vintage lenses survive ok. Guess what? They were being exposed to light and generally dry conditions. Anywhere with high humidity like tropical countries create more perfect conditions for the fungi to grow. Of course a lot of lenses were kept in sub optimal conditions – left in storage for many years in people lofts and garages. Some of these locations provide heat, humidity and of course darkness. Conditions essential for the fungal spores to turn into something nasty like glass eating fungus.

To make matters worse for you but nicer for the fungus is the fact that many older lenses used organic elements in their lubrication. Basically dead dinosaur guts. These organic based lubricants have a tendency to vaporise over time and create the classic lens haze. Lens haze is cleanable in most cases but the organic elements in the oil provide food stuffs for the fungal spores. It’s not a given that a hazed lens will also have fungus by any means but hazy lenses are often hiding fungus in them.

Lens and camera cases - the very worst for fungus — Lens and camera cases – the very worst culprits for fungus.

One of the worst things to store lenses in is leather and canvas bags and lens pouches and of course many lenses were supplied with leather pouches or placed in close proximity to leather like camera bags. Leather and fabric create a great starting point for fungus – its organic for a start and quite often soaks up moisture. People will often wrongly assume one lens has caused contamination of other lenses when all of the gear is kept in the same bag. The truth is much more likely to be one lens has shown signs earlier than the others but the storage is the basic problem. Avoid damp, humid conditions. Get the lenses out in air and periodically expose them to sunlight it’s the dry air and light which keeps fungus at bay.

Given time and a dark and humid environment the microscopic spores grow into various types of fungus and most of these can eat lens coatings and even the glass itself if left unattended.

How to spot it? …Fungus can be very severe and easy observable in lens or it can hidden. The best way to check a lens is a simple torch test. Hold a torch at an angle to the lens and look through the other side. Fungus will show itself as either strands or blooms. Strands look like strands of cotton, blooms look like misty patches in the lens. Even apparently mild fungus can start eating into things so its needs to be get gone pronto. It won’t get better with time. Heres some pictures of what it can look like and a prognosis for the lens.

Mild bloom type fungus in a Minolta MD lens. It’s on the inner face of the rear element group. Cleanable.

Strand fungus getting a start in a Tamron zoom. It’s in between a cemented doublet. Game over.

Bloom AND strand fungus in a Minolta MD. It’s between elements. Coatings will fail and haze with chemicals. Game over.

Fatal strand fungus in a Minolta MD. Fungus is between sealed front elements. Game over.

Minolta 50mm f1.4 - fungus between front elements. — Minolta 50mm f1.4 – fungus between front elements. It’s a sealed unit. Game over.

Minolta MCX 50mm - probably haze rather than fungus — Minolta MCX 50mm – probably haze rather than fungus.
Cleanable but risky due to fragile coatings.

It takes a little experience to know when a lens is cleanable and when it’s not as there are so many different lenses out there with their own issues. It also should be noted that almost any classic lens will have small dust particles in the lens when subjected to a lens test. This is perfectly normal and these lenses would have looked no different back when they were made. It also takes some experience to recognise other lens conditions such as haze and sometimes the anti-reflection coatings in the lens can look like mild haze under a torch test. Haze itself can often be hiding bloom type fungus.

Cleaning fungus from a lens is almost always a risk. There’s simply no way of telling at the outset how well the lens will respond to cleaning and no reputable technician will ever give a guarantee. There are quite a few factors that can affect the outcome.

How much damage has the fungus done? You can’t be sure until you attempt to clean it. It may simply clean away or it may leave behind damage to the coatings or the glass. Can the lens coatings take the cleaning needed? Some lenses have relatively soft internal coatings and these can fail with a simple wipe if the fungus has weakened them. Some coatings cannot cope with the chemicals needed to kill the fungus. These are all part of the game of Russian Roulette with lens cleaning and trying to remove remove lens fungus.

So the bottom line is fungal cleaning is ALWAYS a risk. There just isn’t anyway of knowing in advance without experience.

Cleanable or not lenses — Nikon Ai mostly cleanable, Minolta MC cleanable but risky, Minolta MD – forget it!

To add to the other headaches not all lenses are cleanable. Many lenses have sealed element groups. This is common in lenses from the mid 1970s where manufacturers trying to gain a price advantage over their competitors cut down on components and assembly time by simply building using a plastic encapsulation for the lens groups.

A Minolta MC prime lens usually has separate elements bound together into groups using spacers and threaded rings. Later Minolta prime MDs use only two groups of elements which are each encapsulated in a plastic mounting.
There’s no getting between the elements on some of these lenses so if the fungus is between the elements in a group theres not much that can be done. This type of manufacturing was employed by almost all of the big makers like Nikon, Olympus, Canon, Pentax etc.

Encapsulated elements and individual element construction — Minolta MD on left uses encapsulated element groups – fungus between the elements in a group usually signals end of the line for the lens. Minolta MCX on the right was the last of the high quality construction lenses with individual parts BUT its coatings can be very fragile.

Remove Lens Fungus - Fujinon 50mm f1.8 cleaning — Fujinon 50mm f1.8 using classic construction. All elements are removable and cleanable

Remove Lens Fungus - Late model Olympus Zuiko 50mm f1.8 cleaning — Late model Olympus 50mm f1.8. All of the front elements are bonded into a carrier. Theres no way to disassemble or clean.

Even early lenses where it’s possible to remove individual elements can have booby traps in them. Soft coatings, specific orientation of the elements to one another within the group and even cemented doublets where fungus can grow between the cemented lenses. Plus if you take lens groups apart down to individual elements you will find it very hard to eliminate any dust without a fairly clean environment and a lot of patience.

It’s often stated on forums that UV light will kill fungus. It won’t. While UV may reduce any further damage, it relies on direct exposure to the fungus. Normal glass tends to block UV light so in order for UV to work the lens face has to be directly exposed. I routinely subject any lens that’s been cleaned to a powerful UV light source with the right wavelength to cause the most harm to fungal spores but that’s done while the lens is in pieces. A UV light box also creates ozone which is harmful to fungi so that’s a bonus.

So how do you remove lens fungus?

There’s no single answer to this. It will depend on a range of factors. Can you get to the fungus? If the lens uses encapsulated elements and the fungus is between elements in an encapsulated group there’s no way to get access so it’s a non-starter.

Without some experience of how some glass will react to cleaning its best to be careful. Be mindful of a medical rule which is ‘first do no harm’ and also do as little as possible.

I have seen people advised to take a lens completely to pieces so you can douse everything in Peroxide because spores will be in the lens. This is simply pointless. You will more than likely do more damage in a vain pursuit of inert fungal spores which, if the lens is well kept, will most likely never become a problem.

NEVER remove lens elements from their groups unless you have no choice. Minimise the amount of disassembly within a group to as little as possible and make sure you mark the lens orientation. Some lenses would have had a specific orientation when assembled and once this is lost it’s not possible without very specialised gear to get the lens right again. A second hazard is trying to get lens elements back into their groups without getting more dust in there than there was at the start. Finally, and it cant be overstated, some lens coatings within a group are very fragile and can react very badly to chemicals and improper handling.

Remove Lens Fungus - Nikon AiS with fungus — It’s possible – this is a Nikon AiS. The fungal blooms are hiding in amongst the general haze and drek inside the lens….

Nikon lens after fungal cleaning — …and this is the lens after VERY careful cleaning. Beautiful and fungus free.

Cleaning processes

Here I will relate my own approach which is basically to gradually step up the cleaning process in stages and see how the lens copes. Don’t rush in with strong chemicals. There is much bad advice on how to remove lens fungus online from people who don’t really understand the nature of fungus. I have used these methods successfully on very many lenses and they do work. Generally failures are the result of chemicals damaging the coatings OR fungus eating the actual coating or the glass itself.

Cleaning fungus — Minolta MC 58mm f1.4 – A complete strip down of a lens to ensure fungal kill does not include taking lens groups to pieces!

STEP 1 – Nose Grease. Simple and often surprisingly effective...

What! hang on, what’s nose grease and how the heck does it remove lens fungus? Nose grease is grease from the side of your nose in the creases of the outside of your nose. You can harvest it simply by rubbing your finger along the creases. It was traditionally used by watchmakers of fine mechanical pieces as nose grease has some amazing lubricating properties. It’s just slippy enough, doesn’t dry out and doesn’t migrate easily. It’s also mildly antiseptic.

So, you rub your finger against your nose to harvest a little and VERY gently wipe it on to the fungal area of your glass. Leave it for 15 minutes or so and then gently clean with a small amount of diluted Isopropyl Alcohol (50/50 with water) and the use some breath and lint free cloth to very gently buff the lens. CAUTION some lens coatings have very poor abrasion resistance – even a mild rub with a lint free cloth can take the coatings off. Notable lenses for this include the Minolta MCX series 50mm f1.7 where the front elements inner face can fail spectacularly with very little effort on your part.

Some people report good results using a mild hand cream. Most hand creams use a mild antiseptic which of course kills fungus. I have tried this but it failed to clean the fungus but to be fair on that lens the fungus was quite advanced.

Using nose grease…….I have had a Minolta MD 50mm f1.4 which had fungal strands on its inner faces. This was fortunate as its far more common between the sealed groups. Mindful of how fragile the inner faces on some Minolta lenses can be I used the nose grease method and it worked a treat.

STEP 2 – Isoprop. Yes it CAN work...
Apply some pure Isopropyl Alcohol to the affected area and then blow it with cold air from a rocket blower. See how the lens copes. If it’s cleaned it off then stop. Some strand like fungus will clean off without much effort and very weak chemicals. The name of the game is to try the mildest chemicals first. If the fungus is not well established it may simply wipe off. You wont have gotten the spores so thats why I strip down to clean the lens metal work out and give everything a hit of a UV lamp will help make sure the remaining spores are stunted.
This generally works on very mild bloom or strand type fungus. Isoprop wont kill the spores and its not lethal to fungus but it’s better to go easy rather than risk the lens with strong chemicals if at all possible.

STEP 3 – Peroxide. Lethal to organic life...
Time to get tough. Some fungus simply cant be killed or removed with nose grease or Isoprop. Dilute Peroxide is the start point. Peroxide is lethal to organic things like fungus. Normally I start at about a 50/50 mix with water. NEVER mix Isopropyl Alcohol with Peroxide it creates an acidic mix which can be VERY destructive. Apply the dilute Peroxide with a cotton bud sparingly to the affected area. Clean it off straight away with fresh water as Peroxide is quite a powerful chemical even at low concentrations and you don’t want the Peroxide doing more damage than the fungus. This will normally kill any fungus / remove lens fungus but some lens coatings will fail even with a dilute peroxide.

STEP 4 – Peroxide/Ammonia Mix. Carpet bombing has its risks…
Either apply a higher concentration of Peroxide OR use a mix of 50/50 Peroxide and Ammonia. This is a preferred method of many lens technicians but I am a dissenter on this. My reasons are these; Fungal spores are EVERYWHERE and to guarantee killing all spores you would need to use something like a surgical Autoclave or medical grade UV system ON EVERY SINGLE PART of the lens. Let’s assume you did just that and amazingly the lens could hold up under that sort of treatment – so what? The spores are in everything and the lens could easily be reinfected. Long term fungal protection is in the storage of the lens NOT in chemicals you apply during a strip down. I seldom use a powerful chemical mix such as Peroxide/Ammonia but it does have its uses for very stubborn fungus types.

For Peroxide/Ammonia treatment start with a very dilute mix (diluted with water) and increase strength but be aware once you start using powerful chemicals in strong mixes you can expect to see stuff like coating failure. This will often become apparent when you try to clean the lens afterwards. I have seen spectacular coating failures due to chemicals on the inner faces within element groups of Minolta MC series lenses and have been told by a reliable source that some Olympus lenses will fail in a similar fashion.

If I am using powerful chemicals like Peroxide I prefer to flush the lens with distilled water. It means the lens can be cold air blown dry and pure lab grade distilled water leaves no streaks which reduces any risk of polishing with a lint free cloth in case coatings have been weakened as some coatings have poor abrasion resistance.

A note of caution on ‘polishing. You need to be very gentle. Lenses are figured to wavelengths of light. Excessive or too harsh polishing can cause a lens to lose some of its figuring. You may not believe it but lenses are easily damaged by too frequent cleaning. Remember, you only want to remove lens fungus.

Once the fungus is gone from the glass the spores may still remain…
It’s impossible to get everything dead and as stated in this article even if you could the lens will be ‘breathing’ spores in each time it’s used. Normally though I will run all of the metalwork through a mild detergent or bleach and expose every affected element and all of the lens metalwork to an anti-bacterial UV lamp. A 20-minute exposure will be enough to seriously stunt any remaining spores. I NEVER disassemble groups unless there is no choice. Removing a lens group is easy and it’s possible to then clean all the metalwork involved in the helicoids and barrels. Taking lens groups themselves to pieces is sheer folly unless the fungus is between a group and you have no alternative.
Whenever a lens presents with fungus I will always strip all the metal work and clean it and replace the old lubricants with modern synthetic lubricants which tend not to haze and modern synthetic lubricants deprive the fungal spores with their foodstuffs.

Nikon Ai - unsuccessful fungal cleaning — A Nikon Ai. Despite best efforts the fungus had damaged the coatings on the inner rear element. The fungus is dead but despite the damage the lens still performs very creditably.

Finally… its best not to become overzealous or obsessed. Fungus needs removing as it will only get worse with time. If you run into a lens where after cleaning the fungus has done some permanent damage it’s not the end of the world. The Nikon AI in the picture above is one of my most used lenses. It has slight fungal damage which cleaning could not correct at the edge of its rear element. You would be hard put to spot any difference between it and a mint example in the photographic output.

A general rule of thumb to remove lens fungus… unless you want to learn lens repair it’s best to avoid lenses with fungus for sale. It’s generally not worth the risk unless you are tooled up and happy to gamble. As this article has pointed out cleaning is fraught with risk BUT if that gorgeous Nikon AIS f1.2 or Minolta MC 35mm f1.8 comes into view and its cheap enough it’s maybe worth the chance. Even if you cant fix it a pro might be able to.

Just bear in mind you really do need to read up and practice lens disassembly if you want to try cleaning yourself. You also need a good range of tools. The guides on the site covering some models of lens strip down will, I hope, help you in your journey.

Minolta MD 50mm f1.7 / f2.0- Lens Repair Guide

A step by step guide to repairing the underated Minolta 50mm f1.7 This Minolta MD Lens Repair Guide can also be used for many other short focal length MD series lenses such as the 50mm f2 (which is identical in construction) and the 28mm, 35mm and 45mm MD types. Most short focal length Rokkors share a very similar construction and while there may be minor differences the essentials will be almost identical.

This is NOT true of long focal length and zoom MD lenses which will be very different in design and construction.

The guide covers the late model MDIII series but the earlier MD series with 49mm filter threads will be identical. The earliest MD type with 55mm filter threads is somewhat different.

Copyright 2021 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.

NOTES BEFORE YOU START

The Minolta MD 50mm f1.7 is a relatively easy lens to work on but does have some small challenges – please bear in mind that this is a Minolta MD Lens Repair Guide, you may well face challenges inside the lens that you will need to work out. These can include stripped screws, deformed parts etc.
Read through the entire guide before you start to make sure you understand the basics and are aware of hat you may need in the way of tools and are prepared for any possible problems that may arise.

When working on one side of the lens (eg the front) always be mindful about what’s happening at the other side (eg the back). I always keep caps on as much as possible to prevent any accidents. The classic mistake is for people to press on the lens while it is on a workbench and break things on the downside of the lens like the aperture lever.

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).

There are no prizes for fastest or almost working in the world of lens repair so read the Minolta MD Lens Repair Guide from end to end before starting to familiarise yourself with the process.

Start by putting a rear lens cap on while you work on the front part of the lens.

The quality of any repair is down to your skills, your tools, patience and most of all mindfulness.

Good servicing is taking your time, there are no prizes for the fastest lens strip down and rebuild.

Phase 1 Minolta MD Lens Repair Guide

Remove the lens beauty ring. This will require a rubber cup as there are no spanner slots on the beauty rings of most MD series lenses.

With the beauty ring removed all of the essential screws and fittings for the front part of the lens are exposed.

Start by removing the filter ring retaining screws using a JIS screwdriver.

There are three of these around the filter ring. One of these is indicated in the picture.

Filter ring fittings differ between various versions of the lens. Some have three tabs, some have a fourth tab which sits over and around one of the optical element retainer screws.

Remove the three screws retaining the filter ring. Keep these separate as they are sometimes a different size to the optical element screws which will be removed next.

Remove the three screws retaining the front optical group. One of these is indicated in the picture.

Remove the three screws and keep these separate from other parts.

Exercise caution as these screws are tight, a slip with a screwdriver here can impact the lens.

The front optical unit can now simply be pulled free. Its very common for vaporised grease to have gotten behind this and it may cause the unit to stick. It can be gently pried up using a fine screwdriver or cocktail stick gently under its edge.

Store the front optical unit safely.

With the front optical unit removed the aperture diaphragm blades are exposed. In an MD series these are very thin and very fragile. It’s best to open the diaphragm to maximum to reduce any risks to the diaphragm blades as you move forward.

Phase 2 Minolta MD Lens Repair Guide

You now need to remove the focus barrel. This is retained by three screws around its front edge. These hold in place a brass ring which in turn holds the focus barrel by a ridge around its circumference.

Set the lens at infinity BEFORE removing these screws.

Here’s the brass ring and screws removed. Once these are removed the focus barrel simply slips off of the lens.
The brass ring is sometimes made of thin steel. Keep this safe as it is easily damaged. Before removing the screws set the lens to infinity focus. It’s assumed the lens worked ok at infinity focus prior to strip down, if not the process at the end of this guide will set infinity for the lens.

Measure the gaps between the slots of the two helicoils and make notes as to the gap sizes. In this picture the outer helicoil is to the left and the inner helicoil to the right. I normally use some jewellers screwdrivers to gauge the distance. Its not super critical but it will help with reassembly to know the measurements.

Phase 3 Minolta MD Lens Repair Guide

Turn the lens over and remove the three screws surrounding the rear optical unit with a JIS driver. Exercise caution, these can be tight and you don’t want a screwdriver skating across the rear lens surface.

These screws are usually quite long.

With the three screws removed the small black plate can simply be removed. Note it has a flat side near the aperture control lever.

SPECIAL NOTE: Some very early versions of the MDIII lens do not have this plate. They have shorter screws that fasten directly to the rear optical unit.

With the rear plate removed the rear optical unit will simply be free. I normally use some angled tweezers to grab it by its fitting lugs and extract it.

Store the unit safely.

Phase 4 Minolta MD Lens Repair Guide

Remove the 4 screws around lens mount and store separately.

Once the screws are removed you can simply pull the lens mount free. It’s a good idea to hold onto the aperture ring and keep it pressed down while you do this to avoid any risk that the aperture ring comes off at this point which can result in the loss of the small ball bearing.

Observe the rear of the lens mount assembly. Note the cut out which engages with the diaphragm actuating lever.

Also note the brass liner which runs around the base. Be very careful as the brass liner is not attached, it will normally be held on by grease but can come free very easily. Its is extremely thin and very easily damaged so clean this very carefully with a cotton bud dipped in IPA.

With the lens mount removed you can now see the lens focus lock tabs. Note that one has open sided holes for its fitting while the other has closed holes

Be careful from here on with the strip down. The aperture mechanism in an MD is mostly plastic and the aperture lever is very fragile.

While holding the aperture ring to the lens very carefully set it to about a mid position. This will make it easier to remove in the next step.

Cup the rear of the lens in your hand, preferably inside a Tupperware box or clear bag and gently pull the aperture ring free. Inside the ring there is a tiny spring and ball bearing and these can easily fly out and be lost.

Sometimes the bearing will stay with the lens, sometimes it will fall into your hand. Sometimes it will simply vanish – take this step easy. If you don’t see the ball bearing examine your hands carefully. It’s so small it may be stuck to your hand.

The pic shows how small the bearing and its pusher spring are. The bearing is 1.2mm in most MD lenses.

This is why I generally remove the aperture ring inside a large clean bucket or Tupperware box. It minimises the risk of a loss.

The spring will most normally stay stuck inside the aperture ring but to be sure it is not lost I normally extract it using a cocktail stick to ease it free and store the spring with the bearing inside a secure container.

When I clean/refurbish a lens EVERYTHING gets cleaned, to avoid loss of small parts everything is removed. This is the aperture locking tab being removed.

With the aperture ring removed this will simply push out. It’s ‘keyed’ so will only fit one way on reassembly.

Phase 5 Minolta MD Lens Repair Guide

Before removing the focus helicoil locking tabs note how they are fitted.

They do not press too hard against the side of the helicoil. If these are replaced to tightly they will cause the lens focus to be stiff.

Remove the helicoil locking tabs with a JIS driver making a note of how they are arranged.

The open sided one is away from the aperture lever.

If you are going to face a headache in an MD series lens this will be it. The lock tab retaining screws can be tough to extract.

Chemicals are not an option here except sparingly as they can easily leak into the diaphragm. A Good set of JIS drivers is the only real option for safe extraction of these screws.

Heres one of the lock tabs being extracted.

With both lock tabs extracted the inner and outer helicoils can simply be unscrewed from each other.

The picture shows L-R the inner helicoil, outer helicoil, lens body.

This completes the strip down of the lens.

MECHANICAL CLEANING

All components APART FROM the inner helicoil are now cleaned with hot soapy water and/or IPA. All threads are chased out with a fine bamboo skewer or pin. The outer helicoils threads are very fine and the smallest bit of dirt or dried grease will give the lens a lumpy or gritty feel. A lens shouldn’t be cleaned more often than necessary so you should take pains to get this right.

The inner helicoil is a challenge. On the MD series the diaphragm forms part of the inner helicoil and the diaphragm can not be removed easily. In order to clean the helicoil I place the helicoil on its side on a clean cloth and then gently wipe the old grease off with cotton wool balls. When most of the grease is removed I then use a cotton wool ball moistened with IPA to run around the threads. Too much liquid on the wool ball can easily seep into the diaphragm and cause problems so go easy on liquids and be VERY CAREFUL of the aperture lever

The diaphragm of most MDs seldom suffer with oil contamination so its unusual to have to deal with stuck diaphragms in this series of lenses. If contamination is slight you can immerse the diaphragm in IPA and then air dry. For serious contamination, which is rare, you will need to dissemble the diaphragm which is not covered in this guide.

OPTICS CLEANING

The Minolta MD series usually show haze caused by oil vapour on the lens group inner surfaces. These are the optical surfaces that face inside the lens in each of the two optical groups. These can be cleaned with a mild IPA solution and a lint free soft cloth. You need to exercise extreme care here and do not apply pressure to the glass. Apply a mild IPA solution to the cloth just so the cloth is damp and then apply lightly. Use a puffer brush to blow off any moisture and then use a clean cloth to clean out any evaporation marks by gently breathing on the lens surface.

In the MD series the front and rear optical groups are encapsulated and cannot be removed as individual components. If your lens has fungus or issues between elements in a group there is no repair possible

I normally clean the optics just prior to their reassembly into the lens and make sure the lens interior is blown clean with a puffer bulb. You will always find some dust is present on reassembly – do not worry – they were no different when they came from the factory.

After cleaning the helicoils should be lightly greased using a suitable lubricant. I prefer Helimax XP for most Minolta lenses. This is applied thinly using a fine sable brush. On a Minolta MD series the lubrication needs to be slightly thicker on the inner helicoil thanks to its plastic surface. The outer helicoil needs to be very thinly lubricated or else the lens focus will be too stiff.

Notes on lubrication – The first time you so this you will need to work by trial and error to get the right feel.
Too much lubricant will result in the focus being stiff, too little and it will grind or be too light. You can test the ‘feel’ while the helicoils are assembled but it will be hard to assess without practice as to what the lens will feel like with its focus barrel mounted.

Phase 6 Minolta MD Lens Repair Guide

On reassembly the object is to get the helicoils spacing for focus the same as you measured at the end of Phase 2 and…

…with the lock tab locating holes in the right position for the lock tabs to engage with their slots.

You may need to unscrew the lens a few times and reassemble to get this correct.

You can see in the picture that the locating holes for the tabs are correctly orientated for the tabs to fit into the slots.

Replace the lock tabs. This is the most fiddly thing with an MD series and supercritical on the 45mm f2 lens.

Here I am using a bamboo skewer to keep the tab in position while the first screw is put in. The tabs can easily twist and turn while being replaced…

…and can impact the side of the lens. The tabs do not need to be in close contact with the edge of the lens or else they will cause the lens to jam. They also need to be flush with the top surface of the lens body when the lens is fully pulled back.

If the helicoil gaps are set correctly at the start of Phase 6 then it may be the tabs stand a little proud with the focus pulled back as far as possible. This is not usually a problem but you must remember not to reassemble the rear of the lens with the tabs proud of the rear surface or the aperture mechanism can be jammed.

Phase 7 Minolta MD Lens Repair Guide

Replace the aperture lock tab if you removed it earlier.

Replace the aperture ball bearing spring if you removed it at the end of PHASE 4. Seat the ball bearing on the top of the spring using a small blob of Helimax XP grease.

While keeping a close eye on the bearing (and preferably doing this step inside a large Tupperware box or bucket)…

…trap the bearing in place by applying the aperture control ring at a slight angle to trap the bearing and then ease the rest of the aperture control ring down over the body of the lens.

NOTE: You will find it easiest if you trap the bearing under the aperture ring with the aperture control ring set at about a mid point.

Before attempting to refit with the bearing do a couple of dry runs so you know what to expect.

Immediately after fitting the aperture ring test the aperture ring f stops are nicely clicking.

Making sure the aperture control ring doesn’t slip off turn the aperture ring to its highest value the highest value (smallest aperture)

NOTE: Some versions of the 50mm MD series only go as high as f16 but the MDIII will go to f22.

Double check that the helicoil lock tabs are flush with the top edge of the lens body as described at the end of Phase 6

Phase 8 Minolta MD Lens Repair Guide

Place the lens mount over the lens and check that the diaphragm actuating lever is captured by the cut out in the mounting rings lever mechanism and place the lens mount onto the rear of the lens……

…. Now rotate the lens mount until the screw holes align with their fixing points. If all is well the lens diaphragm will stop down as you turn to the lens mount around to match the F16 or f22 setting.

In the picture a skewer is being used to hold the mount in place at the correct position.

Secure the 4 screws that retain the lens mount to the lens body. Do not overtighten these as the threads can strip quite easily. They need to be firm but not gorilla tight.

Generally I leave these quite loose at this stage and only tighten down once I am happy the lens is working correctly. Check at this stage that the aperture is working correctly by activating the lever. Check also that the lens focus is working by turning the outermost helicoil. Do not wind the lens too far out or it can slip off the lock tabs at this point just turn it a quarter turn at most to ensure the focus is free and operating.

Phase 9 Minolta MD Lens Repair Guide

Replace the rear optical assembly making sure its screw hole are aligned with the fixing points beneath. I use a cocktail stick to move the optical unit around and check that the holes are aligned to their fixing points.

Blow the lens clean before reinserting it.

Replace the rear plate making sure the flat side is located against the aperture lever and the blackened side is facing outwards (eg would face into the camera when mounted).

Replace the three screws that secure the plate and the rear optical group and then secure a rear cap to protect the rear of the lens.

Phase 10 Minolta MD Lens Repair Guide

Replace the front optical group. The lens should be blown clean prior to replacement.

Replace the 3 screws that secure the front optical group.

Phase 11 Minolta MD Lens Repair Guide

Attach the lens to a known good camera, look through the viewfinder and use the outer helicoil to bring the lens to infinity focus.

I normally aim at a pair of radio towers around 8 miles away and use a camera with a split field focus.

If all is well with focus gently put the focus barrel over the lens and make sure the infinity mark is against the index line. The barrel will also be set against the focus stop.

Carefully position the focus barrel locking ring to align with the three fixing positions.

A bamboo skewer is helpful for positioning this.

Fix the focus barrel locking ring with the three screws. Do not overtighten as these will shear easily.

A good test of tightness is to hold the screwdriver between thumb and forefinger and roll the screwdriver between your fingers. This will take it to just tight enough.

Recheck focus at the end of this and if needs be release the screws a little and shift the focus barrel around. This can be fiddly to get perfect – take your time and don’t rush.

The filter rings come in differing styles for MD lenses. This one has a position that fits over one of the lens fixing screws as shown.

Replace the filter ring and replace the screws holding it in place. You can see in this picture the short tab which simply goes over one of the front element retaining screws.

Cosmetically when the lens is at infinity the edges of the focus barrel and the filter ring shoulder should be almost flush. So long as the helicoil measurements were correct on reassembly this will be as close as you can likely get.

Replace the beauty ring….

…and use a rubber cup to tighten down. Take care with this as the filter ring is metal while the beauty ring is plastic. Make sure it is correctly threaded before attempting to tighten down.

Take a final check and make sure the lens is operating correctly, focus at infinity is ok and all f stops and stop down are working correctly.

Notes on The Minolta MD 50mm f1.4 Lens

The f1.4 version of the MD lens is somewhat different. The basic process described for the f1.7 or f2 versions is the same but there are some differences in construction.

1/ The Filter Ring
The filter ring on the f1.4 version is part of the front lens body. With the beauty ring removed you will see two small grub screws. Remove these and then simply twist the enire front of the lens away which includes the filter ring.

2/ The Front Optical Element
The front element is retained by three JIS screws.

3/ The Rear Optical Element
Unlike the f1.7 and f2 versions the rear optical element is not retained by the use of screws. It is screwed to the rera of the diaphragm assembly. You will find this easiest to remove with the lens mount and aperture ring removed. You may need to use some Isoprop to break down the thread lock.

4/ The f1.4 most usually only has a single helicoil lock tab.

The actual process for stripping down, rebuilding and setting infinity focus is otherwise identical in most respects.

Minolta MC ROKKOR 58mm f1.4 – Lens Repair Guide

This Minolta MC Lens Repair guide can also be used for many other short focal length MC series lenses such as the 55mm f1.7. Most short focal length Rokkors share a very similar construction and while there may be minor differences the essentials will be almost identical. For our guide on Minolta MD 50mm f1.7 / f2.0- Lens Repair Guide click here

This is NOT true of long focal length and zoom Rokkor lenses which will be very different in design and construction.

This Minolta MC Lens Repair guide covers the MCII series but MCI series will be identical.

This guide will NOT be appropriate for MC-X Series, MD Series or the earlier Auto Rokkor models which all employ very different construction.

Copyright 2021 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.

NOTES BEFORE YOU START

The Minolta Rokkor 58mm f1.4 is a relatively easy lens to work on. Please bear in mind that tis is a guide, you may well face challenges inside the lens that you will need to work out. These can include stripped screws, deformed parts etc.
Read through the entire guide before you start to make sure you understand the basics and are aware of hat you may need in the way of tools and are prepared for any possible problems that may arise.

When working on one side of the lens (eg the front) always be mindful about what’s happening at the other side (eg the back). I always keep caps on as much as possible to prevent any accidents. The classic mistake is for people to press on the lens while it is on a workbench and break things on the downside of the lens like the aperture lever.

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 advise from people who know less than you.

There are no prizes for fastest or almost working in the world of lens repair so read the Minolta MC Lens Repair guide from end to end before starting to familiarise yourself with the process.

Phase 1 Minolta MC Lens Repair

Remove the lens beauty ring. This can be done with a lens spanner but a rubber cup is a better solution. A lens spanner can easily mar the finish on the beauty ring.

With the beauty ring removed all of the essential screws and fittings for the front part of the lens are exposed.

Phase 2 Minolta MC Lens Repair

Start by removing the front optical element group. You will see there are two sets of lens spanner cut outs. You need only the outer pair.

Apply the lens spanner and gently but firmly turn the lens while keeping downward pressure on the spanner.

The front optical group after being unscrewed can be simply lifted out of the lens body.

Store this somewhere safely. I usually store lens groups in a Tupperware box lined with lint free cloth pending cleaning and reassembly.

You are advised not to disassemble this group but cleaning will be discussed later.

With the front optical group removed the aperture mechanism is now exposed…….

It’s safest at this point to open the aperture to its widest. This will minimise risk of damage to the very fragile aperture blades as you move forward in the disassembly.

Phase 3 Minolta MC Lens Repair

Using a JIS screwdriver remove the three screws that retain the filter ring…..

…and simply lift the filter ring away. Make sure the screws are stored safely and not mixed up with other screws. I normally allocate small dishes for the various screws and fastenings to avoid confusion later.

Phase 4 Minolta MC Lens Repair

You now need to remove the diaphragm assembly. This is retained by 4 screws around its edge.

One of them is highlighted in the picture….

Using a JIS screwdriver remove the four screws around the aperture mechanism…..

….and remove the diaphragm assembly carefully. The rear optical group is still attached to this so extract this with great care so that the rear optics are not damaged.

Here is the diaphragm assembly rear view after removal. You can see that the rear optical group is still attached. It is far easier usually to remove this group with the diaphragm removed.

Take great care of the diaphragm assembly, it is fragile and easily damaged by rough handling.

Take note of the fact that the assembly has a flat edge on one side. You will see why later.

Phase 5 Minolta MC Lens Repair

With care unscrew the rear optical group. Be careful here as the diaphragm assembly has a number of small parts at the rear and the pins and springs can be easily damaged. Remember to stay mindful, keep focused, and THINK before you act.

Store the optical groups somewhere safe while you move forward with disassembly.

Here are the two optical groups from this lens being stored in a small Tupperware box line with lint free cloth.

Phase 6 Minolta MC Lens Repair

Check the diaphragm assembly for correct function and see whether there is oil contamination. If the oil contamination is light I usually spray the diaphragm out with a Freon free cleaning solvent and then let it bath in Isoprop Alcohol for around an hour before leaving it to dry thoroughly at room temperature.

If the unit is heavily contaminated it will require stripping down completely.

Diaphragm strip down and rebuild is not usually required and this guide will not cover this aspect.

Phase 7 Minolta MC Lens Repair

Now it’s time strip the focus mechanism for cleaning and lubrication.

Set the lens focus to infinity.

It’s assumed that the lens focused correctly prior to stripping down but if not don’t worry it will be corrected later.

Start by removing the three screws around the edge of the focus barrel with a JIS screwdriver. These are on top of the brass coloured ring. Take care to extract each screw after removal and be careful – each of these screws has a tiny washer – DO NOT LOSE THEM.

Once removed, store them safely.

With all three screws removed the focus barrel will simply slip off from the lens body….this reveals the two focusing helicoils.

These go by different names but to keep life simple the guide will refer to the brass colored one as the outer helicoil and the silver colored (inside the brass one) one as the inner helicoil.

Measure the distances between the inner helicoil to the brass helicoil – normally on an MC lens the inner helicoil will be almost flush with the brass outer helicoil.

Measure also the gap between the brass helicoil and the lens base. Normally I use a collection of fine screwdrivers to assess distance. In this case a 1mm driver is being used and it is an exact fit. Make a note of these measurements.

Phase 8 Minolta MC Lens Repair

Now remove the lens mount assembly from the rear of the lens body. Start by removing just a single screw. If the screw is short then replace it. If it is long remove it.

DO NOT REMOVE THE SHORT SCREWS

Here is a picture to give you an idea of scale of the short and long screws.

These alternate around the lens mount plate. You only need to remove the 4 long screws for servicing of the lens. Removing the short screws will release parts of the lens that are difficult to reassemble and generally there is no need to remove these parts.

With the four screws removed, as before store them safely and then simply pull the lens mount assembly from the body of the lens.

Take care also at this point NOT to remove the aperture ring. I usually tape the aperture ring to the body prior to this step to make sure it does not come away with the lens mount due to stuck grease.

Phase 9 Minolta MC Lens Repair

Sometimes the bearing will stay with the lens, sometimes it will fall into your hand. Sometimes it will simply vanish – take this step easy. If you don’t see the ball bearing examine your hands carefully. Its so small it may be stuck to your hand.

This is why I generally do this inside a large clean bucket or Tupperware box. It minimises the risk of a loss.

The previous picture and this one give an idea of size – the bearing is most normally around 1.2mm.

In the previous picture the bearing is sitting on top of a small spring. This bearing and spring provide the click stops.

Store the bearing somewhere safe.

Place some low tack tape over the hole with the small spring to prevent loss or remove the spring entirely.

A small needle, needle nosed tweezers or a cocktail stick can be used to extract it. Store this safely with the bearing. The spring is very tiny barely larger than the index numbers on the lens, take care when handling it as it is prone to flying off and getting lost.

Phase 10 Minolta MC Lens Repair

Remove the three screws from the helicoil key/lock tab.

Be careful here as these are sometimes lacquered in place. If they don’t turn out easily apply some heat or isoprop alcohol.

It’s very easy to strip the heads on these so take care.

Remove the helicoil key/lock tab.

Unscrew the helicoils from the lens body.
Its good practice to count the turns before the parts separate and mark the separation point on the two parts.
Its not necessary for the 58mm f1.4 MC but it is good practice – not all lenses are kind to technicians.

L-R in picture – lens body, outer helicoil, inner helicoil.

Note: The inner helicoil has screw holes in its top part – this faces the front of the lens when assembled.

This completes the strip down of the lens.

We now have to consider cleaning the components and reassembly.

MECHANICAL AND BARREL PARTS – NOT INCLUDING DIAPHRAGM MECHANISM

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 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.

OPTICS CLEANING

The Minolta MC series can show haze caused by oil vapour on the lens group inner surfaces. These are the optical surfaces that face inside the lens in each of the two optical groups. These can be cleaned with a mild IPA solution and a micro fibre or lint free soft cloth. You need to exercise extreme care here and do not apply pressure to the glass. Apply a dilute IPA solution to the cloth just so the cloth is damp and then apply lightly. Use a puffer brush to blow off any moisture and then use a clean cloth to polish out any evaporation marks.

CAUTION

You are advised NOT to remove the lenses from within each group. Minolta used a very soft coating formula in almost all of the MC series lenses and this can be damaged by even very mild cleaning and careful handling.

After cleaning the helicoils should be lightly greased using a suitable lubricant. I prefer Helimax XP for most Minolta lenses. This is applied thinly using a fine sable brush. On a Minolta MC series the lens is semi self lubricating thanks to the material used in construction of brass to aluminium so the lubricant needs to be quite thin and very evenly spread.

Notes on lubrication – The first time you so this you will need to work by trial and error to get the right feel.

Too much lubricant will result in the focus being stiff, too little and it will grind or be too light. You can test the ‘feel’ while the helicoils are assembled but it will be hard to assess without practice as to what the lens will feel like with its focus barrel mounted.

Phase 11 Minolta MC Lens Repair

On reassembly the object is to get the helicoils spacing for focus the same as you measured at the end of PHASE 7 and with the lock tab recess aligned to the threaded holes for the lock tab. You don’t have to be super precise but its best to get it as close as possible. You may need to unscrew the helicoils a few times and try at different entry points to the threads to achieve this.

Replace the focus lock tab. Take care not to overtighten the screws.

After replacing check that the helicoils will rotate correctly. The lock tab, if not centred can cause the focus to jam or be stiff. I normally apply a very thin smear of Helimax XP to the sides of the recess.

Phase 12 Minolta MC Lens Repair

Do a trial run of fitting the aperture ring to the rear of the lens. Some MCs will be fussy about what position the ring needs to go back on (eg will only easily fit at the f5.6 position) Do a dry run if needs be BEFORE replacing the small ball bearing.

The trick to get the bearing back into position is to replace the spring and then apply a small dab of lubricant/grease to the top of the spring. Apply the bearing to the grease to hold it in place.

I normally position the bearing by using a cocktail stick with a small dab of grease on its end to retain the bearing….

…keep the lens body in position while you keep an eye on the bearing and the apply the aperture ring at a slight angle to trap the bearing in place and then ease the aperture ring down over the rest of the lens body.

This is why you do a dry run earlier at the start of Phase 12 to make sure the ring will fit easily as some MC lenses will be awkward to fit the aperture ring at some positions.

While making sure the aperture ring does not slip off apply the lens mount to the rear of the lens body making sure the aperture actuation lever is at the base of the lens and on the opposite side of the lens to the aperture index mark.

You can see in the picture the aperture index mark is on the opposite side to the aperture actuation lever.

Replace the four long screws into the lens mount ring. Do not overtighten these for now.

This is in case anything is wrong and requires a quick strip later. Just tight enough is good enough for now.

Phase 13 Minolta MC Lens Repair

In order to replace the diaphragm mechanism you need to be aware of some elements of assembly.

Th diaphragm barrel has a flat side as shown in the picture. This has to locate against the lens body where the focus lock tab sits…..

….here is the focus lock tab and the flat part of the diaphragm barrel needs to be aligned with this PLUS…..

The diaphragm actuating lever shown needs to locate into the aperture control ring slot on the lens body……

….The aperture control locating slot is shown here. This is where the Diaphragm body lever needs to mate to.

It seems tricky but in fact its quite easy. Here’s how to do it…

First set the aperture control ring to f2…..and by using the diaphragm barrel lever at its rear open the diaphragm to its widest aperture.

Place the diaphragm barrel into the lens making sure the flat side is aligned with the focus lock tab.

Look through the rear of the lens body – this is why you leave the rear lens element out during reassembly until this step…..

..and maneuverer the diaphragm and the aperture ring until the diaphragm lever is located into the aperture control ring slot.

This seems hard at first but you will see it is actually quite easy in practice.

Once diaphragm is installed hold it gently in place and rotate it slightly so that the screw holes align.

Cap the rear of the lens to protect the aperture lever and replace the screws that retain the diaphragm barrel to the lens body. Do not overtighten as these can shear off under too much torque.

Once secured check that the diaphragm is behaving normally by selecting f16 and operating the aperture actuating lever. The aperture should stop down and reopen quite normally. Check also operation at f1.4

Phase 14 Minolta MC Lens Repair

Replace the rear optical group…..

I would normally clean the group before reinsertion and blow the inner surface clean.

….and secure the group with a lens spanner.

Replace the front optical group…..

These would be cleaned at this point and the inner surface blown clean with a Rocket Blower.

Prior to securing the front lens it’s a good idea to run a quick torch test before the lens is fully secured down. This may catch any pieces of dust or lint prior to final assembly.

…and secure with a lens spanner.

Phase 15 Minolta MC Lens Repair

Attach the lens to a known good camera look through the viewfinder and use the brass inner helicoil to bring the lens to infinity focus.

I normally aim at a pair of radio towers around 8 miles away and use a camera with a split field focus.

Once you are happy that the lens is focusing correctly set the lens at infinity and then very carefully replace the focus barrel making sure the barrel indicates infinity against its index mark. Replace the focus barrel retainer screws with their washers and lightly tighten. Recheck focus and once happy tighten down – do not over-tighten as these screws will shear easily.

Replace the filter ring.

Replace the beauty ring. Take care to ensure this is correctly threaded before tightening down with a rubber cup or lens spanner.

Check lens for all functions and do a final tighten on the mount ring if you left this loosely dogged down at the end of Phase 12

Fully check lens focuses correctly and that all f stops are working correctly.

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

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

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

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

Nikkor-S 35mm NAI Lens – Stripping Down

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

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

Further Reading

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

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

Further Reading

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

Repairing the rubber grip on the 45mm f2 MD Rokkor

Minolta MD Rokkor 45mm f2 Repair Guide – Reassembly

Further Reading

Nikon 50mm Repair Guide – NOTES BEFORE YOU START

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

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

Nikon 50mm Repair Guide f1.8 AiS – Disassembly

Nikon 50mm Repair Guide f1.8 AiS – Reassembly

Notes on the Aperture Control Spring

Further Reading

Nikon E Series Repair Guide – Disassembly

Nikon E Series Repair Guide – Reassembly

Further Reading

Further Reading

Further Reading

Further Reading