Repair: Micro-Nikkor-P 55mm f/3.5 Auto

Hello, everybody! Did you miss me? I sure missed you. I am currently very busy at work and it is taking a toll on my body, in fact I had to take a rest yesterday because I’m just so tired. I’m currently heading 3 projects because I am a versatile employee. Being versatile is good because you can be useful but being versatile also means that your skills are kind of spread thin. This is a common problem if you’re not a specialist before you acquired a second skill. In my case, I’m a specialist at the technical side of the business and the other things that I do are things that I happen to know enough of to make big decisions for the company. If I were to be a Nikkor, which lens would I be? We will see.


Today, I will show you one of the most versatile lens designs that made it into production and became so successful that it spawned copycats and a legacy that lasts to this day when it came to the essence of the idea – the awesome Micro-Nikkor-P 55mm f/3.5 lens!

img_3042I really love this lens, the all-metal construction is tough and the ergonomics are perfect! You can’t get any simpler than this and this lens is so practical that it’s still relevant today as a general-purpose normal lens. This lens spawned copies from other manufacturers in it’s day from rival companies all the way to small obscure brands. It is a successful design!

Before this came to be (in Nikkor-land), specialist lenses do specialist things and normal do normal things. One such specialist task is macro-phorography where a lens is expected to perform great in high magnifications. To achieve this, photographers back in the day had to use bellows and some kind of high-performance enlargement optic specially made for a task and nothing else. There was an attempt by Nikon to bridge the gap by engineering the epoch-making Micro-Nikkor 5.5cm f/3.5 lens. There was an earlier lens for the S-mount but it was made for the Nikon-S line of rangefinders (Leica fit,too) but how one got to focus it precisely with a rangefinder is something beyond me. The Micro-Nikkor 5.5cm f/3.5 lens was big step towards making a macro lens that can perform “just as well” for normal use but it was awkward to use as I will explain in the next paragraph.

IMG_1976bThis image shows you the differences between the original Micro-Nikkor 5.5cm f/3.5 and the the Micro-Nikkor-P 55mm f/3.5 Auto that replaced it. I will now explain the big jump in the design philosophy between the two lenses . The older lens can go all the way to a 1:1 (life-size) magnification ratio on it’s own but in order to do that, the lens has to extend to great lengths. This makes for an awkward-handling lens and since the objective is situated so far to the front away from the lens mount, a reliable way to actuate the iris automatically was impossible to engineer and implement at that time so this lens had to be a preset-aperture type meaning that you have to stop-down the lens manually before you shoot. This is very cumbersome as you first compose your shot and then manually stop down the lens before you click and in the field this can mean a lost shot. Not all is bad with this because the lens had a very good optical design that just needed a new and more practical solution for it to be more useful and easier to market to people who want a more versatile tool.

The solution was to do away with the 1:1 native magnification ratio that is the cause of the problem and since not everybody shoots at this high magnification on a daily basis it was decided that 1:2 is good enough. This allowed for a more robust lens design and the most important part is that the lens now has an auto-aperture function in-line with the other Nikkors for the F-mount, this is one of the reasons why the SLR came to be the dominant design for cameras for the decades to come anyway – convenient and precise focusing.

IMG_2326Here are the major mechanical variations of this (55mm) lens family, from the first one on the left all the way to the last one to the right. The lens we are showcasing in this blog post is the 2nd one from the left. Isn’t it a beauty? They are all beautiful to me!

fullsizerender-25Here are all of my Micro-Nikkor-P 55mm f/3.5 Auto lenses (for now). Some people collect or hoard shoes, watches, etc. For me, this is my thing. I simply have to have these little gems and all of it’s versions. What you see in the picture represents all of the known variations of this lens that went on sale. The variations are in the engravings, paint and differences between early and later versions of the lens, which I will discuss in this blog post in the disassembly portion.

The lens extends quite a bit when you go from infinity all the way to it’s minimum focus distance and it can  achieve a magnification ratio of 1:2 (50% of life-size) when the lens is fully extended. This sounds like it’s more of a devolution from it’s predecessor which can reach 1:1 (life-size) on it’s own but there is a very important ergonomic reason for this and we discussed that in the previous paragraphs. The only time that a lens from this family’ll reach 1:1 on it’s own again is in the ’80s with the Micro-Nikkor-AF 55mm f/2.8 lens.

img_2039Here, we have an earlier version with the silver nose. I like this lens a lot as it looks really good, specially when mounted on a silver and black camera. It kind of reminds me of the mosquito from Egypt that carries dengue fever. I have a strange mind.

IMG_2810.JPGIn order for this lens to achieve 1:1 magnification, you will need to have one of these. These are sold together with the lens if when you buy them new back in the days. If you are lucky these days, you can even find one in it’s original box and bubble case along with it’s little manuals, M-ring (as these are called) and other relevant goodies.

IMG_2956.JPGThese lenses also come with an Ai-uprade ring. It is rare to find one with a ring but I will tell you that it’s easy to get one from it’s successor (with the rubber grip) and then attach it to this lens since both lenses share the same aperture ring design. I do not know if this was what happened to this lens or it was indeed officially modified by Nikon but it’s all OK.

(click images to enlarge)

I don’t have much time to shoot some samples from this lens so please pardon my sample pictures this time. The infrared pictures were shot with a Nikon D70s converted to IR and the coloured ones were shot with a Nikon D750. The 55mm focal length makes it an ideal walk-around lens with the added perk that it is also a macro lens. The pictures from this lens are sharp even wide-open and from my experience is pretty good until f/16. The sweet spot for this lens is somewhere around f/5.6-f/8, f/11 is still pretty but the images “pop” at f/8. It is said that this lens performed poorly at infinity so Nikon updated the formula a bit on one of it’s successors. I personally do not find this necessary as I don’t use this lens for shooting far-away subjects anyway, I use another lens for that.

This lens is also nicknamed the “compensating version“. It is called by that name since the lens is engineered so that the aperture opens up as you focus closer to compensate for the lost light due to the elongated lens barrel. This was important back in the day but is kinda obsolete so the next version did away with it. I will show you how Nikon achieved this later in the disassembly section so I hope that you will read the whole article.

This lens can be impractical to use on the field at 1:1 magnification because you have to be really close to your subject in order to achieve that magnification ratio. Not only will you be getting in the way of your lighting but you will also scare away shy bugs! Now, I am not saying that this lens is useless in the field but I am just saying that it will have limited use for that purpose. But this lens has a nice flat field and is incredibly sharp so it has another use for many – slide and document photography! Coin and stamp shooters will also like it as well where having a flat field is non-negotiable for obvious reasons.

img_3069Here is my setup for copying slide/strip film. I use a Nikon ES-1 for slides, a modified ES-1 is needed for strip film to avoid damaging the film and I will discuss that next time. Here, it is mated to a PN-11 extension ring because the PN-11 has a tripod mount.

Ok, I think I wrote more than I should so let’s go straight to the disassembly portion!

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 (Front):

The lens itself is pretty easy to work with. In fact, I can even advise an beginner to work on one provided he has the correct tools and a good steady pair of hands. It is has a basic but elegant design and the engineering is simplified to perfection.

I will break down the disassembly into a few steps because of the differences between the early and later models. The differences do not matter much but I just wanted to be sure I am clear about everything here you won’t screw this up if this is the first lens you repair in your entire life.

img_3043Begin by removing the 3 screws securing the focusing ring. As you can see from the picture the screws are of the (+) type. I am not sure that this is original, the previous guy who had his hands on this lens probably salvaged the original (-) screws for himself? Very likely.

img_3044The focusing ring should come off easily. I have never worked on a lens from this version that had it’s aperture ring glued. Old and caked grease may cause it to stick at times so use patience and wiggle it until it comes off.

Older Nikkors were built with tight tolerances so focus adjustments were not needed. This made the lens expensive to make because of the high quality control – a Nikkor hallmark.

img_3045Now that the focusing ring is out of the way, we are now free to remove the front barrel. It is being secured by a tiny set screw so just unscrew it and leave it in a safe place. I sure lost a few of these little things as they are incredibly tiny.

img_3046Unscrew the front barrel and be sure that the lens is facing down or else the objective may drop to the floor. That is a sure and easy way to produce a junk lens.

img_3047Carefully pick the objective out and grab it by it’s impressive casing. Set that aside first so it will not be damaged while we work on the rest of the lens. Be careful of the bulbous rear element! Scratching that one will make this lens worthless.

img_1128On the early version of this lens, the objective is secured by 3 screws so remove them first before you pull the objective off from the lens barrel. Notice that the front barrel screws in to the objective’s casing instead of the inner helicoid.

Disregard the picture above if you have a late version lens!

OK we can now continue with the rest of the lens. Pay attention as I will shift between the early and late versions of the lens.

Disassembly (Rear):

The difference between the early and late version of this lens is most obvious in the rear part of the lens where the bayonet mount is situated. Very early Nikkors do not have screws on the bayonet mount’s exterior for a variety of reasons that Nikon only knows but I guess that it’s mostly for aesthetics and cost-cutting  (you will know why I said that soon).

(Late Version):

We will start with the late version since the lens that we have now is a late version lens. It is simpler to work on the late version since there are less things to think about. Skip this if you have an early version lens and head to the next section unless you want to read this.

img_3048Start by unscrewing these 5 screws. This lens has been worked on by somebody else before and he used plenty of glue on these. Normally, I would apply a couple of drops of alcohol or solvent into each screw head and let it work for some time before I attempt to remove the screws again but I do not want to sit on the cold wooden floor on a cold winter’s night so I brought out the mini butane torch. I torched one of the screws for a couple of seconds until I am convinced that it is hot enough to soften the glue. While the thing is hot, I grabbed a long shafted screwdriver (use JIS drivers only!) and with the weight of my elbow against the driver I slowly turned until the screw gave. I did this to the rest of the screws, just be sure that you cover the black enameled parts with something to protect it from the flame or else it will ruin the surface of the paint. As with everything that has to do with fire, use commonsense and caution.

img_3049With the screws gone you can now pull the rear bayonet off from the rest of the lens. Look at the baffles on this lens, Nikon wants to make sure that you do not damage that delicate bulbous rear element. I do not advise that you take this apart, just look at all those balls!

img_3050Before you begin removing the aperture ring, be sure to remove this screw first. This screw serves as a pin to connect to the aperture fork inside which in turn connects to the delicate iris assembly in the objective. Forcing your way isn’t possible and you will just damage it.

img_3051When the screw is gone, you can safely remove the aperture ring from the rest of the lens.

(Early Version):

The early version of the lens looks elegant and neat without all those screws in the rear. It is also multiple times more expensive to produce because there are more steps involved in it’s manufacture as you will soon see. This section is useless for people who have the later version of the lens but if you are interested then just hang around and learn.

img_1106What is this? No screws!? How do I open this thing? Follow me and I will show you how.

img_1111First, begin by removing this big screw. This screw connects to the aperture fork inside the lens barrel and the aperture fork is connected to the iris mechanism in the objective.

img_1116Unscrew the aperture ring from the rest of the lens but be very careful not to damage the delicate threads found on both the aperture ring and the bayonet or you will not be able to replace the aperture ring again normally.

Next, remove the small screws that are found in the circumference of the thread found on the lens barrel. There are 2 of these in the picture and there may be 5 or 6 of them in the actual lens. Be careful as they are sometimes glued and use a screwdriver that fits snuggly, if you don’t you will ruin these. File a precision screwdriver to fit these if you don’t have one that will fit properly in the slot of the screw’s head.

img_1120With those screws gone, simply pull the rear bayonet off from the lens barrel. Notice that it is milled from brass, how awesome could that be? This is the 1960s, where things were built to last a lifetime (and a nuclear war)!

Disassembly (Helicoids):

We can now go back to something that is similar to both versions of the lens. The helicoids are pretty long on this lens, it has to be since this is a macro lens. Just imagine if this lens goes all the way to 1:1 magnification and how long the helicoids should be in order to make that possible! I like it this way, nice and compact.

img_3052We will begin by removing the chrome sleeve. Unscrew these 3 screws carefully and also be careful not to damage the knurling  on the grip by using a smaller screwdriver.

img_3053The sleeve comes off just like that after the screws are gone. Just look at all that oil under the sleeve! The sleeve is seldom glued but it may get stuck due to caked lubricants so don’t force it and just apply some solvent to soften up the gunk that got caked underneath it.

img_3054Before separating the helicoids, I made a line on the surface of the outer, central and inner helicoids so I will know how the alignment should be later on when I reassemble the lens.

img_3055To free the helicoids, simply unscrew these 2 large screws. Be careful with these as they’re often held in place with epoxy and if they are, you will need head these up or use powerful solvents to soften up whatever was used on these. These smell of peanut butter so it most certain that epoxy was used. Do not force it, I had to use a screw extractor more than once on this part because the screw head snapped (decapitated?).

img_3056The screws secure the helicoid key. The helicoid key makes sure that the helicoids move in sync as you rotate the central helicoid, extending or contracting them – manual focusing!

The helicoid key fits into a slot on the inner surface of central helicoid. Be sure to study it properly and how the mechanism works before you take it apart.

You do not want to damage anything that has anything to do with this part or you will end up with a stiff or rough focusing lens so keep this thing safe.

img_3057Now that the helicoid key is gone, you can now separate the helicoids. In this picture, I got the outer helicoid to separate from the central helicoid and I marked where they separated with a small arrow that points to a line as a point of reference. Be very careful and be sure to mark this because this is also the same spot where the helicoids should mate. If you got this wrong or forgot to do this then you are in for a long and painful time guessing where the helicoids should mate. This can drive you nuts and frustrates a lot of beginners.

img_3058As with the previous pic, I also marked where the inner and central helicoids separate. I’m very particular with this because I failed a few times before and I do not want you to waste hours of your time trying to get this back properly. Be sure to read my blog post on how to work with helicoids before you attempt to do this.

img_3059Late version only. You can now access the aperture fork now that the helicoids are free. It is in charge of how much the iris closes down each time the stop-down lever is depressed. Notice that yellow thing to the left, that is what remains of the epoxy that was used on the helicoid key that I talked about a few steps prior. That thing has to go!

img_3060Carefully unscrew the aperture fork and it’s ring from the lens barrel and make sure not to damage the delicate threading. It is milled from a soft aluminium alloy.

img_3061Notice that the slot on the aperture fork is slanted instead of straight. This is necessary so that as you focus your lens closer, the iris opens up. This is a clever trick to compensate for the lost light as the lens gets longer and hence the unofficial nickname of “compensating” that is given to lenses of this type, now you know.

img_1121Early version only. The aperture fork mechanism can be unscrewed from the bottom for the early version of this lens. Notice the slot in the thread, that is where the pin should go.

This one goes for both versions. When reassembling the aperture ring, make sure that the hole/slot in the aperture fork mechanism lines up with the hole for the pin on the aperture ring and if you got this wrong you will ruin the threads in the aperture fork mechanism. To avoid this, I use a thin wire and insert it into the hole for the aperture ring and rotate the aperture fork mechanism inside until the wire slides through the hole there as well. This is what I do to ensure the the holes line-up properly before I put the pin back.

img_1132At this point, you should have something that looks like this. This is the early version lens but since the major parts are very similar to the late version, then this should also apply to it as well. The dirty parts will be wiped clean and dunked into an alcohol bath for removal of residues and odours. After pickling overnight in the bath, the helicoids will be brushed with pig bristle brush in a Dremel to further remove any residue from the old grease. They will be re-wiped, cleaned and picked with a toothpick later on just to make sure that all of the helicoids are free from anything that was there to make sure that the new grease will not be contaminated and end up fouling up the lens later on. This is a complete overhaul.

Disassembly (Objective):

The objective is nearly identical for both versions of this lens and the differences are not as obvious as with the case of the bayonet mount so this section applies to both the early and late versions of the lens. The objective shown here comes from an early type lens, I had to mention this fact just to be clear.

Some of the parts may be glued so you will need a few drops of acetone or alcohol but most importantly, you will need a rubber stopper of the right size to open up the front part of this lens. If you still do not have one in your kit then it is time to look for one or to make one yourself. Alternatively, you can use a thin rubber glove and the bottom of a medicine bottle so long as it fits properly. Cover the rubber glove over the medicine bottle and then carefully press it against the front of the lens. This is a hack so be careful.

img_1139This is the objective, the casing itself is impressively big with 1/3 of it functioning as some kind of hood. Do not bother removing the screws that you see here unless you intended to overhaul the iris assembly,too. This lens is not prone to the oily iris problem so I guess you will not have the need to open the iris assembly up.

img_1140First, you will have to separate the front elements group from the objective’s casing. Look at the picture above and you will see a seam in the inner surface of the front “hood”. This is where they should separate. While trying to remove the front elements group, you may accidentally remove the name ring. That is OK, you will just need to screw that thing back carefully later on. This just gave you the chance to cleanup whatever is underneath that.

img_1142The front elements group should come off like this along with the cone that’s a part of it.

img_1144To open up the front elements assembly, simply separate it along this seam. As you see in the picture above, somebody else worked on this lens before and he left a mark there along the seam. If it is glued, you should place a drop of alcohol to soften up whatever was used on it. Normally, this thing can be unscrewed with your bare hands.

img_1145Be very careful when you separate these as you might scratch the glass or anything might make a free-fall to the floor. Some of the elements are glued in place so do not bother to remove them from where they are mounted.

The one on the left houses the 2nd and 3rd lens elements, they are both glued together to form 1 lens group. This lens group is usually glued to it’s housing so don’t bother getting it off or you will just risk damaging this. The part on the left houses the 1st element and it is also glued to it’s own housing. Again, don’t bother getting it off from it’s housing.

img_1153All looks clean and clean from here so I will just leave the iris assembly alone.

img_1155The rear elements group consists of the 4th and 5th elements. Simply use your fingers to unscrew the rear elements group from the objective’s casing. The 4th& 5th elements can be accessed by removing a retention ring found on the housing. I do not have any pictures of those so I apologise.

That’s it for the objective. The optic is very simple anyway, 5 elements in 4 groups.


I hope that I did not confuse you with all that switching between early and late versions. I was initially thinking of splitting this into 2 different blog posts but since the differences aren’t so big I tried to condense them into 1 blog post. I will try to avoid doing this in the future as it prevents me from showcasing a lens individually even if the changes are small.

Going back to the Micro-Nikkor-P 55mm f/3.5 Auto, the lens was so well-engineered so even after I have overhauled many samples of this lens, I seem to never get tired of working on another one. I am getting so familiar with this that nothing seem to surprise me anymore every time I work on one. I am not claiming to be the world’s leading authority on this lens but maybe one day in the near future, I will be. You got to be good on at least one thing in your life, right?

I usually do not give notes on reassembly because it is commonsense that you follow your notes backwards and study how each mechanism works before you take it apart but I will give you some pointers on how to put this thing back together the easy way.

For this and the majority of older Nikkors, I would reassemble the objective back as a unit so it is kept safe as opposed to just leaving it all over the place and vulnerable to accidents. It is also worth noting that leaving the objective scattered about will only invite more dirt on places where you do not want them. I would then reassemble the lens barrel back but leave the focusing ring out for focusing adjustments as well as some other parts that will just get in the way of the objective when I finally decide to mate it back to the lens barrel,etc.

img_3062This tall-head screw should go into this slot in the aperture fork. I reassembled the lens up this point wherein I left out the bayonet because the stop-down lever is there. You can do this step after putting back the rear bayonet but this is easier and it works for me.

img_3063For the late version lenses, make sure that this screw on the objective’s casing front is safe and secure in this slot. For early lenses, just align the screw holes and put the screws back.

img_3064Finally, align the stop-down lever to the tab sticking out of the objective’s casing. Be sure not to scratch the rear element while doing this! As you can see in this picture, my fingers are keeping the objective from coming off from the lens barrel and dropping to the floor.

I guess that is it for the reassembling bit. This lens is made very precise that no focusing adjustments have to be made provided that you reassembled your lens properly. Quality control was this high back in the days for Nikkors.

img_0345Here are some of this lens’s brothers. I own several of these because I just like taking them apart and restoring them back to perfect working condition while I admire the engineering and care that went into creating this masterpiece. I just cannot have enough of these!

 And there you go! This one took me several nights and a day to compile so I hope that you liked this one. I will try to write something next week but given my increasingly busy life, I may write something short next or maybe skip a week altogether. See you next time and I hope that you keep yourself warm this winter! 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.


12 Comments (+add yours?)

  1. Trackback: Repair: Micro-Nikkor 105mm f/2.8 Ai-S | Richard Haw's Classic Nikkor Maintenance Site
  2. Trackback: Internet Nikon Repair Resources – My Take on Photography and Diving (Underwater Photography Mostly)
  3. Bent Hjarbo
    Apr 12, 2017 @ 13:23:33

    What are the differences to the Ai model?


    • richardhaw
      Apr 12, 2017 @ 14:53:15

      Hello, Bent!
      Optically, not by much but this one is sharper at 1:1 but the Ai is better at infinity. You will not notice much when you stop-down. Ric.


  4. Trackback: Repair: Auto-Nikkor-P 105mm f/2.5 | Richard Haw's Classic Nikkor Maintenance Site
  5. Trackback: Articles Index | Richard Haw's Classic Nikkor Maintenance Site
  6. Trackback: Negative Digitization with a Nikon DSLR | Richard Haw's Nikon Maintenance Site
  7. Trackback: World of F-mount Nikkors (2/3) | Richard Haw's Nikon Maintenance Site
  8. Trackback: Repair: Micro-Nikkor-P.C 55mm f/3.5 Auto | Richard Haw's Nikon Maintenance Site
  9. Trackback: Repair: AF-Micro-Nikkor 55mm f/2.8 | Richard Haw's Nikon Maintenance Site
  10. Trackback: Report: Nikkor Prototypes (Part 1) | Richard Haw's Classic Nikon Repair and Review
  11. Trackback: Repair: Nikkormat FTn part 1 | Richard Haw's Classic Nikon Repair and Review

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: