Repair: Micro-Nikkor 5.5cm f/3.5 (1/2)

Hello, everybody! I was busy with my life and work in the past couple of weeks so I was not able to update this blog. In order to make amends, I am going to write you guys something special! Please read on!


Today, we are going to discuss a very unusual, rare and historical lens from Nikon. This is something that you do not see everyday and as a consequence, there is not a lot of info on the net about this lens. Many people do not even know that this thing exists!

The Micro-Nikkor 5.5cm f/3.5 is the lens that started the popular 55mm line of macro lenses from Nikon. This lens line was so popular and practical that other manufacturers needed to copy the concept behind this lens and incorporate it into their own lens line!


I am not going to discuss on the lens’ performance and history that much since you are obviously here because you want to know how to repair this lens or know more about the engineering behind this thing. In case you want to know those things then you can go to Matthew Lin’s excellent writeup on this lens here (insert Jeremy Lin jokes here).

To get down to 1:1 magnification natively without the help of extension rings, this lens has to extend this much. It looks impressive for people with phallic inadequacies but I can tell you that the handling suffers a lot because of this feature. The camera is a Nikon D7200.

IMG_2729On this lens, you first set the desired aperture using the aperture ring and then you stop it down manually before you press the shutter (after composition and focusing). This is a lot of work even for studio and this is the reason why this lens had a short production life. The first picture actually shows the 2 rings clearly so you guys should also check that out.

It’s successors will only focus down to 1:2 magnification without the included M extension rings but the handling has been improved considerably. Only during the mid 80’s with the introduction of the Autofocus Micro-Nikkor 55mm f/2.8 will we see a lens from this lineage regain the ability to focus back to 1:1 magnification without the help of extension rings or other attachments.

IMG_1944This is how close you need to be in order to focus down to 1:1 magnification. This is close to useless for shooting bugs on the field or anything with ambient lighting as you will get in the way of the light source. Using strobes or LEDs will help you illuminate things but just take a look at that distance!

IMG_2691Notice that the shape of the iris is not round but star-shaped in this lens. This will create some interesting bokeh balls. Here is an article on how to work with preset-type irises and there are videos there. Check the link out for more information.

This lens will also NOT focus to infinity on modern Nikon bodies and will only focus out to 1m or around 3ft because the focus ring is too narrow and will get in the way of the bayonet mount found on modern Nikkors. You can modify this lens to fit and focus properly on the modern Nikon cameras and I will show you how (you can only find this info on my blog!).

IMG_0198This lens can focus to infinity just fine on older Nikons before the AF era as you can see.

There are so many things that I can teach and show you about this rare lens and 1 blog post alone is not enough so I am going to split this into 2 posts! This part will only deal with the overhauling of the lens barrel and the second part will deal with overhauling the objectives  and modifying this lens to fit modern Nikon cameras (AF era) amongst other things.

IMG_0149.JPGThis lens also comes in 2 minor versions. One with a raised filter thread (far right) and the original one with the flush filter thread (left and middle). Occasionally, you will see that I have used pictures from both versions to construct this post so please keep that in mind. The differences are minor so it should not matter. They are 9/10 identical!

Enough with all the talk. Let us now begin dismantling this lens!!!

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.

Disassembly (Main Barrel):

Dismantling this lens is pretty straight easy once you know how it should be done. It took me a plenty of hours (and pain) to figure out how to dismantle this thing because I cannot find any information on the net on how to go about doing things.

The lens can be separated into 2 main parts:

  1. Focusing unit (lens barrel)
  2. Objective (optical block) and the front part

This lens is very odd and you will find a lot of unorthodox engineering as far as manual focus F-mount Nikkors are concerned. It is a bridge between the past S-mount for Nikon rangefinder cameras to the F-mount so it should be an interesting project or read for you.

IMG_2693First, remove the 3 bayonet screws to get rid of the bayonet mount…

IMG_2694Once the 3 screws are gone, the bayonet should easily come off. As you can see from this picture, the grease has migrated into places where it shouldn’t. This is a sign that the lens was poorly restored or kept and should be overhauled as soon as possible.

IMG_2695This step is unnecessary for the usual grease replacement but if you want to do a thorough overhaul then you can remove the rear baffles  by unscrewing the screws that secure it to the bayonet mount. There is felt in the baffles so be careful not to ruin it.

IMG_2696This metal retention ring is the only thing that holds the objective to the rest of lens barrel and if you can see the slots on the picture then that should give you a good idea on how to remove this.

IMG_2697Use the flat side of a lens spanner and carefully unscrew this metal ring and be sure not to accidentally scratch the exposed rear element. Any damage on the rear element can easily show up on the resulting image.

IMG_2698Once that metal ring is gone, the objective and the rest of the front assembly should slide out effortlessly. Be sure not to drop it accidentally as it is heavy enough to free fall to the floor.

IMG_2699This brass ring is responsible for adjusting the this lens’s infinity focusing as well as help keep the objective in place. Do not lose it as it is unique to each lens.

Store the objective in a safe place to protect it from accidents and contaminants. Now that the objective is gone, you can safely work on the rest of the lens barrel without having to think about it.

IMG_2700To undo the helicoids you should first remove this plate by unscrewing these 3 screws. This plate is where the objective is seated and it is a very important part of the lens because it keeps 2 important things together.

IMG_2701Once the screws are gone, focus the barrel closer to the minimum focus distance to give it some space for you to manoeuvre the plate so that you can pull it out of the barrel. Notice that the plate is clipped on both sides.

IMG_2702As you can see from the picture above, the clipped edges are essential for the plate to exit the tight opening of the rear barrel.

IMG_2703Once the plate is gone, the helicoid keys are now exposed. These keys can be removed by unscrewing these for screws. The keys are broken in to their respective slots so I highly recommend that you mark one of the keys and it’s slot so that you will know which one goes where later on when you reassemble your lens.

IMG_2704Be careful when handling the helicoid keys as they are made of plastic. I am actually very turned off by this because I expect that Nikon should have known better by using metal on something as important as these. How these survived 6 decades, I don’t know.

IMG_2706Things can get a bit confusing from this part on because you will have to go back and forth to disassemble this lens further.

To remove the chrome grip, carefully remove the 3 screws that secure it to the lens barrel. Be careful not to scar it with your tools because it is made of a soft aluminium alloy.

IMG_2707Once the screws are gone, you can safely pull the chrome grip down to reveal more screws and the spring mechanism used for the preset aperture ring.

IMG_2708Of course, you cannot remove it because the focusing ring is in the way. To remove it, just unscrew the 3 screws that secure it to the lens barrel.

IMG_2709And off it goes…

IMG_2710The chrome grip can now be safely removed.

IMG_2711Next, remove the 3 screws that hold this ring down. This thick metal ring is responsible for keeping that large spring in place when the lens is assembled.

IMG_2712Be careful as you remove this as you do not want the spring’s tension to release and cause anything to fly across the room!

IMG_2713The preset aperture ring can now be safely removed. Notice the notches on the edge of the ring. Each notch corresponds to it’s own respective aperture number.

IMG_2715To remove that big brass cup, start by removing these 3 screws.

IMG_2716These 2 pillar screws have to be carefully removed as well. These are delicate so use care as you unscrew each one of them.

Pillar screw A is used to click the aperture in place while pillar screw B is used as a stop of some sort for the aperture stop-down collar (whatever that thing is called).

IMG_2717Now that all those screws (5) are gone, you can now safely remove this huge brass cup.

IMG_1975You should probably have something like this by now.

Disassembly (Helicoids):

Now that the other stuff are gone, you are now free to concentrate on the helicoids!

IMG_2718Start by removing the outer helicoid. Be sure to mark where they separate as well because failure to do so will result in hours of agony trying to figure out where they should mate.

IMG_2719Do the same for the inner helicoid as well.

IMG_2720These screws are responsible for another set of keys inside the barrel. These screws are not interchangeable as you can see why later.

IMG_2721Here is the other one. Notice that it is smaller.

IMG_2722removing the screws will also free the keys/nut under it. Sorry for the poor “macro” photo coming from an iPhone 6s.


During reassembly, please do not forget to reassemble this before you apply any grease or you will have a messy time. Also, do not over tighten these or you will have a squeaky lens. Just tighten it enough to the point that it feels secure and not wobbling about.

IMG_2723Now that the keys are gone, this brass coupler is now free to go. This part enables the lens to extend to silly lengths (about 3x?) just to give you the ability to focus all the way down to 1:1 magnification.

Grease the outer surface of this part later during reassembly. If this part is dry, this thing will rattle or shake as you zoom in and out.

Disassembly (Objective):

For people who just want to work on the objective, you can skip the previous steps and go straight to this part.

IMG_2724Start by removing this pillar screw. This thing is responsible for linking the front cone to the iris mechanism in the objective. Rotating the cone will open or close the iris. Also be sure to mark the position of this thing so that you know how much you should turn this cone in when you reassemble your lens. A picture is also sufficient.

IMG_2725Once the pillar screw is gone, simply unscrew the cone until it separates from the objective and also be careful not to damage the fine threads accidentally. Grease this part lightly to ensure a smooth movement.

Look at how tiny the objective is!


Overall, this lens was a joy to service coming from somebody who collects Nikon’s 55mm line of lenses. It may take you more time than usual to service this because of the long and complicated parts of the lens.

You also need to be careful not to accidentally lubricate any part of the lens that does not need any grease such as the iris assembly. As you can see from the pictures, this lens has a tendency to become very oily over time as grease migrates here and there over time. This is unavoidable in some instances but you can minimise it by carefully applying the grease to each part of the lens that needs it. Do not use to much grease on the helicoids as well. A thin film of grease on each surface of the helicoids is more than enough. Also, do not use a heavy grease for this lens in the hopes of wanting a damped focusing sensation. The heavy grease will only make your focusing undesirably heavy and you might end up disappointed and wishing that you used a lighter grease type instead.

IMG_2726This is how thing should line up when reassemble your helicoids.

IMG_2727This time with the brass cup attached.

Be sure to organise your screws properly because this lens has plenty of screws and they also tend to look alike even if they are not. This is most apparent on the screws located on the aperture ring assembly and spring mechanism.

The plastic helicoid keys also needs to be handled properly. Damaging these is something that you do not want and milling one from brass or aluminium is also not an option. There is a reason why Nikon chose to use plastics instead of metal and one of those is because they want to avoid excessive wear to the brass extension coupling inside the helicoids.

IMG_2730Here it is now, shiny and clean! I hope that you enjoyed this blog post and also please look forward to part 2 where we will discuss how to clean the iris as well as how to enable this lens to focus to infinity on modern Nikon cameras. Thank you again and as always, please feel free to share this post because this is the only in-depth guide available on the net for this unusual and rare lens. Love, 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.


17 Comments (+add yours?)

  1. Jan Riedijk
    May 15, 2016 @ 11:55:02

    thanks very much 🙂


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  11. JEan-PHilippe
    Apr 04, 2018 @ 08:38:42

    Hi Richard, I am about to restore a Micro AI-s nikkor 55mm -/2,8. The focusing ring is very stiff, it is almost impossible to turn and adjust. I have read a lot about how to remove old grease, apply new grease on helix, and I was wondering if the S-30 grease available on micro-tools would fit. I want a focusing ring be smooth, silky that youp can move with two fingers. You advise and experience is most welcome. Cheers from Switzerland


    • richardhaw
      Apr 04, 2018 @ 09:32:07

      S30 will be too thick for that. All of the helicoids working together will make it stiff. Use S10 but don’t use too much as my article states. Read my other articles on lensss with CRC to know more. Ric.


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