Repair: New Nikkor 55mm f/1.2

Hello, everybody.

I have been busy the whole week with the unbelievably overcomplicated and ill-reputed Zoom-Nikkor 43-86mm f/3.5 so I have not updated the blog in a week. I would also like to thank my readers for the growing support that you are showing me. All that support will keep me motivated.  I am also happy to know that there are many people who share my passion that some are now starting to share their knowledge in the internet.

It is time for another lens teardown and I am going to write this guide for a friend that is why I chose this lens instead of the other ones that I have in my repair notes.


The 55mm f/1.2 lens started with the Nikkor-S 55mm f/1.2 lens and then it got updated to the K (New-Nikkor) version and lastly into Ai. The subject of our post is the 2nd version (K).

This lens is what many people call the “poor man’s NOCT” because it opens all the way up to f/1.2 and the focal length is also close to 58mm. While the NOCT is in a totally different category of specialty lenses, this lens is designed to be a normal lens best used at night for more light and easy focusing due to the brighter viewfinder. This lens was also a product of an industry wide race to produce the fastest normal lens at the time and this lens was only discontinued when it’s successor, the Ai-Nikkor 50mm f/1.2 came into production.


This lens can produce amazing subject isolation when shot wide open, but this lens also has a tendency to produce harsh looking bokeh (I hate that word) if the correct variables were given such as foliage. Just look at the picture above and judge it for yourself…

The lens itself is sharp wide open in the centre when focused properly but the artefacts that it produces when shot at f/1.2 makes the image look unsharp. Having this in mind, you can actually exploit this to you own advantage because this will also make the skin “glow” under the sun or when lit with a powerful enough light at night, making the skin look clear and the resulting picture “flattering” and surreal.


This is also the lens that I grab first whenever I want to produce a painterly like effect. The 50mm f/1.2 Ai-S can do the same thing but just not as dreamy as what this lens can do. Just look at the picture and you can see what I am talking about. The lens is around 4 decades old but the pictures that it takes still looks lovely and full of character. This trait is missing in modern lenses that were overly-corrected and that is one of the reasons why I am buying older Nikkors at the present and the poor quality control issue in recent years is another reason as well.

I got this lens in a pretty OK state as the glass was clean and free from blemishes or small scratches. The lens however had a slightly dry helicoid and a misshaped aperture. The iris was not even (a bit oval) so I skipped this lens the first time I saw it but since the rest of the lens is OK anyway and I figured that I could fix the aperture myself so I got the lens the next time I saw it in the shop.


This lens was pretty easy to work with, very straight forward and orthodox. The only time that I felt scared was when I was handling those big chunks of glass because I do not want to scar the lens accidentally.

If you have been following my blog, this will remind you of the Nikkor-S 50mm f/1.4 lens I blogged about a few weeks before as the assembly was pretty straight forward and similar in many cases.

Before We Begin:

If this is the first attempt at opening a lens then I suggest that you read my previous posts regarding screws & driversgrease and other things. Also read regarding the tools that you will need in order to fix your Nikkors.

I highly suggest that you read these primers before you begin (for beginners):

Reading these primers should lessen the chance of ruining your lens if you are a beginner. Also before opening up any lens, always look for other people who have done so in Youtube and the internet. Information is scarce, vague and scattered (that is why I started this) but you can still find some information if you search carefully.

I highly recommend that you also read my working with helicoids post because this is very important and getting it wrong can ruin your day. If I can force you to read this, I would. It is that important!

For more advanced topics, you can read my fungus removal post as a start. This post has a lot of useful information here and there and it will be beneficial for you to read this.

About Me:

I am a photographer based in Tokyo who scours the junk section of the camera shops here on a regular basis. I started this hobby of fixing old lenses and cameras because I kept on getting scammed before when I purchase online. This turned out to be a blessing because I now buy junk lenses for a fraction of the price and then fix them to add to my growing now collection. This allowed me to buy gear that were otherwise off-limits to me if I were to get them in better condition.

I was a scale modeller before who built models for other collectors for a very longtime, got an education as a dental prosthodontist (but didn’t pursue dentistry) and growing up in a watch repair shop gave me the useful skills that would help me in this craft. Fixing my car also contributed some know-how.

Having mentioned the above, I will tell you now that I am not a professional repairman! So please take what I do with a grain of salt and I will never be held responsible for anything wrong that will happen to you and your project. I hope that the pros would guide and teach us but nobody is writing anything.

As my collection of repair notes grew, I get requests from people with similar interests and from professionals who just needed some notes just in case. Now, I am sharing my library with you for your entertainment and reference. I hope that you find my work useful.

Disassembly (Lens Barrel):

This lens is very typical of the Nikkors made in this era. There’s nothing noteworthy in this lens’ barrel construction that I must mention apart from the slightly brittle type of rubber used for the focusing ring. Nikon decided to use softer ones for their later lenses so I find it odd that they used something like this for this lens.

IMG_1433First, rotate the focusing ring until you see this tiny set screw and loosen it just enough so that you can rotate the front ring without this set screw coming in contact with the fine threads underneath.

IMG_1434Remove the front ring and store this properly because you do not want to warp this part accidentally. We are going to remove the objective (lens assembly) first so that we cannot damage it accidentally as we work on the lens.

IMG_1435Carefully pull he objective out of lens chassis with your fingertips and be careful about that brass ring. It is responsible for adjusting the focus of your lens as well as a washer so that the fit is tight.

IMG_1431Now, remove the screws that secure the rear bayonet plate. Ignore the fact that the lens assembly is in the picture. It should not be there if you have followed my previous steps.

IMG_1432Remove the bayonet plate. The aperture ring can easily be removed at this point. As with the name ring, store this properly because you do not want to bend or warp this or else you will have a rough feeling aperture ring each time you turn it. Again, Ignore the fact that the lens elements are still in the picture.

IMG_1437Now, carefully remove the rubber sleeve and be sure not to rip or puncture it. With that rubber sleeve gone, you can remove these screws. Be sure that your lens is focused all the way to infinity from this point so that you know where are working from each time you remove a part from the lens itself.

IMG_1438Gently pull the focusing ring off from the rest of the lens and clean all the dirt and grime from it. I would also suggest that you dunk this in an alcohol bath to soften up whatever is there for easier clean up later on.

IMG_1439Carefully examine and mark the infinity position of the helicoid in relation to the rest of the lens as this will serve as a guide later on when you reassemble your lens. Notice that I have removed the chrome grip from the lens by first removing the 3 screws that secured it  to the lens barrel.

IMG_1440Next, remove these tiny screws that secure the helicoid stop and be sure to mark which way should forward as reference.

IMG_1441Remove the helicoid stop and store it properly. I accidentally bent mine and I had to fix it on my cylindrical anvil with a rubber mallet. Not a big deal but it certainly is something that you want to avoid if you can.

IMG_1444You can safely remove the sleeve earlier if you want. It just did not occur to me so I got rid of it this late. Clean this and leave this to pickle in the alcohol bath as this part normally gets really dirty on the inner surface.

IMG_1445With that gone you can now access the helicoid key and it’s 2 screws. Remove these small screws so that you can freely unscrew the helicoid.

IMG_1446Be very careful to document and mark where the helicoids separate. I scribed an arrow mark in relation to the line that mark where infinity should be as a reference on where the helicoids separated as this will be the same point where they should engage when it’s time to reassemble your lens.

IMG_1447Drop the helicoid key into your palm and clean it up…

IMG_1448The inner and main helicoids still look great even after 4 decades, just dirty and dry.

IMG_1449As with the main helicoid, mark where the inner and main helicoids separate. If you look at the picture, I marked mine in reference to the notch in the main helicoid.

IMG_1452Now you are left with the outer helicoid/lens barrel. If you need to clean the bearings, just remove the copper retention ring and that should come off. Be careful with the spring by the way. I got lazy and just left these alone as I do not want to go through all the bother by opening this up and having to install the ball bearings one tiny piece at a time.

IMG_1450You should now end up with the same thing as I have in the picture. Next, I will outline how I dismantled the objective.

Disassembly (Objective):

The glass elements used for this lens are HUGE! Be careful not to damage any of them or you will end up with an expensive paperweight. Always proceed with caution and don’t get overconfident, a slip of the wrist may ruin your day. If anything isn’t unscrewing easily then you just have to apply some alcohol or solvent to soften up any glue that was used, wait for the solvent to do it’s thing then have another go at it.

IMG_1456I began by removing the rear elements assembly from the rest of the objective by simple unscrewing it. If it is stuck, do the acetone trick that I described in my best practices blog post to soften up whatever adhesive they have used on this thing.

IMG_1457The front elements assembly simply screws off. In this picture, I just had it sitting on top of the front name ring for no reason at all.

Disassembly (Iris assembly):

You can skip this step if you do not need to clean or repair your aperture assembly. I had to on mine, so I am sharing my repair notes with commentaries with you just in case you have to do it on yours.

IMG_1458First, remove the screws that secure the aperture assembly. Be sure to mark where the screws are because these were precisely secured in place and you do not want to be off my even a millimetre! Notice that I have removed the screw in the picture.

IMG_1459Now is a good time to inspect (actually before the previous step!) the aperture assembly and document it before you disassemble it. It is very delicate and precise and you should be very careful with each step.

IMG_1461Carefully remove this mechanism and store it in a safe place. Be sure not to damage the tiny spring and mark where this thing was before you removed it.

IMG_1462Next, remove this plate after carefully noting it’s position. Notice that one of the aperture blades has fallen off (oops!).

IMG_1463Remove the rotation plate and you can now safely remove the aperture blades.

IMG_1464Be careful when handling your aperture blades, you do not want to accidentally scratch or bend one out of shape, rendering your lens useless except for shooting wide open.

Post Mortem:

Here are some of the things that I did during reassembly that might interest you. I do not write reassembly procedures since it’s common sense anyway, you just backtrack and you should be fine. I will only mention things that are noteworthy.

IMG_1455Having cleaned the helicoids thoroughly, I applied ample amounts of grease so that the focusing is damped enough but not too much as to leave a pile of gunk inside the lens that would later cause grease migration and foul up the aperture blades and glass elements.

IMG_1466The aperture blades were carefully put into place and the iris now forms a lovely uniform shape. The aperture blades were easy to fix as they are of the traditional type and not the same type as what the original Micro-Nikkor 5.5cm f/3.5 (preset) and other vintage lenses have, which is a painful interlocking mess like this one from Brian’s site..

The lens was reassembled within a short time. Aside from the usual precise position and alignment check, the only thing that gave me the most headache was putting the optical block (the objective) back into the lens chassis. This lens is packed inside so it took me a bit of time to get that back in place properly. There is a trick that I do where in I lower the optical assembly in and out until both the aperture column and the auto-lever column are both in place and then I lower the whole thing once I am sure.


This lens took me the whole afternoon (3 hours?) to service and was quite enjoyable to be honest because the lens itself was engineered to be simple and there were no clever tricks used in the lens chassis that would require a lot of figuring out to take apart and put back together.


Here it is with it’s successor, the Nikkor 50mm f/1.2 Ai-S, which is reputed to be a pain to service because of the many interlocking parts inside. Although they share the same spot in product placement and use, each has their own special trait that you should exploit in order to maximise their strength and make the weaknesses work for you.

I hope that you have enjoyed my latest post. For my next post I will try to make one where we dissect an AF-D lens as this makes for a good subject since we already tackled fixing a zoom on the previous repair project.

If you learned a thing or two and would like to support me in this passion please feel free to share this and in the future, click on the links and banners in my page so that I get a few cents every time an add got clicked. This whole Nikkor repair blog project was started without monetary gain as one of the primary considerations but since I have already paid for the domain name (for easy searching) I might as well get that $18 a year back if I can.

Thanks again and I really do appreciate the growing readership of my blog. Until the next post, Ric.

Help Support this Blog:

Maintaining this blog requires money to operate. If you think that this site has helped you or you want to show your support by helping with the upkeep of this site, you can simple make a small donation to my account ( Money is not my prime motivation for this blog and I believe that I have enough to run this but you can help me make this site (and the companion facebook page) grow.

Helping support this site will ensure that this will be kept going as long as I have the time and energy for this. I would appreciate it if you just leave out your name or details like your country and other information so that the donations will totally be anonymous it is at all possible. This is a labor of love and I intend to keep it that way for as long as I can. Ric.


21 Comments (+add yours?)

  1. Ron V.
    Feb 07, 2016 @ 22:08:15

    Again, very nice work Rick.
    Thanks for sharing.
    While not a technically brilliant lens, it is however one of my favourites.


  2. richardhaw
    Feb 08, 2016 @ 00:20:40

    sorry, I mean the 55 f/1.2!


  3. christophe
    Mar 10, 2016 @ 03:38:15

    Hi here!
    Anyone any idea where to get a ring to convert the type 4 version non-ai to ai?


  4. Toby
    May 02, 2016 @ 02:06:58



  5. Charlie
    Jun 03, 2016 @ 08:54:54

    AFAIK to access aperture blades on 50 f/1.2, three lenses from the front must be removed from lens barrel


    • richardhaw
      Jun 03, 2016 @ 09:05:54

      Hi, Charlie. If i recall it, you can remove the front optics assembly in one piece and you can access the blades. But I think you have to remove the whole objective from the lens in order to access the 3 screws holding the retention ring itself. I may be wrong, I have a 50 1.2 dust cleaning post here somewhere, might be better to just reference that.


  6. DanWhye
    Jun 13, 2016 @ 04:24:14

    just bought a fungus ridden Zoom-Nikkor 43-86mm f/3.5.for cheap
    would really love to see how you dismantle it! thanks


  7. Trackback: Repair: Noct-Nikkor 58mm f/1.2 Ai-S | Richard Haw's Classic Nikkor Maintenance Site
  8. Trackback: Internet Nikon Repair Resources – My Take on Photography and Diving (Underwater Photography Mostly)
  9. Trackback: Repair: Nikkor-S.C 55mm f/1.2 | Richard Haw's Classic Nikkor Maintenance Site

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