Repair: Micro-Nikkor 55mm f/2.8 Ai-S

Hello, everybody! It has been a long busy week again for me and I really apologize for not posting in a timely manner. I was busy with work and my family as usual and since spring is just around the corner, I am down most of the time due to hay fever. In fact, I’m currently a bit dizzy as I type so please forgive me if I have typographic or grammatical mistakes. Time flies very fast and my baby is going to be 1 year old soon and this blog is on it’s 1st quarter now. I hope that I can maintain this blog for as long as I can and I am happy for the support that you are giving me. I’m pleased by my growing readership and some of my new readers request that I do an article on a classic, the Micro-Nikkor 55mm f/2.8 Ai-S. This lens has a reputation for the tendency to develop oily aperture blades so it ends up being in the most-requested list. This lens can be difficult or complicated so this post will be longer than my usual so please bear with me as I explain how to break this down as easy as I can for beginners to service this lens.


The Micro-Nikkor 55mm f/2.8 Ai-S is probably one of Nikon’s most popular lenses ever. It was introduced in late 1979 and is still currently produced at the time of writing. This is a really good lens and it’s difficult to replace something that’s so useful. Sure, most new lenses today can auto-focus and other fancy features but there will always be a need for a basic no-BS macro lens for scientific or medical purposes. A simpler lens will be much-more reliable in the field as there are less things that will get broken and since it doesn’t need power to operate it’s going to be better to adapt it as a “dumb” optic for instruments in the field or lab. There are currently 3 successors to this lens but people still buy these for the said purposes and more.

IMG_1061Compared to the previous versions, this lens has a completely-new optical design and it’s also packing Nikon’s CRC technology. It has a simple 6 elements-in-5 groups formula that gives excellent results and later ones have modern coatings applied. It’s a small, compact lens that balances perfectly on any type of Nikon SLR camera and makes for a great lens for travel and general photography. Of course, it’s great as a macro lens and many lenses are compared to it to this day when it comes to resolving power for reproduction jobs or product photography. It’s also useful as a lens for scanning your film because it has a flat field and there’s nearly no distortion in the pictures it creates. The faster f/2.8 maximum aperture is helpful for focusing, attach extension tubes to it and you will see a difference because any tube you add takes-away more light and so your viewfinder gets dimmer. If you are using a camera with a split-prism you may also not be able to see what is behind the prism because there’s not enough light. If you think this is terrible then try using the older Micro-Nikkor-P.C 55mm f/3.5 Auto to see what I mean because that lens is slower so your viewfinder will be darker.

IMG_2326.JPGThe 55mm Micro-Nikkors for the F-mount have a long pedigree starting with the first one made in 1961. I have an affinity with this lens family since I shoot candid street portraits everyday and bugs when they are in season. I also occasionally get the odd request to do product photography and 55mm is just OK for that, giving me a more natural perspective as opposed to the 105mm that I also use. Longer focal lengths can make your subject look flat due to compression, you don’t want that kind of look in your product photography.

The 55mm lens family has evolved throughout the decades that it has been in production with the last (manual-focus) one being the subject of our article today. I would also like to note that the last lens in this lineage, the AF-Nikkor 55mm f/2.8 has identical optics to the Micro-Nikkor 55mm f/2.8 Ai-S so I included that lens in the family.

IMG_2327This is how much it extends to achieve 1:2 magnification. In order to achieve life-size or 1:1 magnification, you will need an extension tube (PK). This PK extension tube is sold or packaged along with this lens when brand new but is usually lost or just not included in the deal when you buy it used. The correct model for this lens is the Nikon PK-13, it’s not cheap buying these new and used ones cost a bit more than other models.

This lens is so good that it’s said that some companies use this for industrial purposes. Its sharpness and flatness of field is perfect for industrial use that even NASA had a special version made for them to bring to space.

(Click to enlarge)

Here area some pictures of the customized NASA version. Check this special article and see more NASA-related Nikon equipment and what are the differences with the standard production models are. Owning this lens is a dream for me. Nikon, please that lens to me!

We can generally assume that manual-focus Nikkors are tough and can handle plenty of abuse in the field and this lens is no exception. All lenses have their own weaknesses and for this particular one, the CRC unit (its main selling point) is its weakness because there is one more thing that can fail in the lens when abused or used for a long time. If that is soiled or if the lubricants turned-bad then it can cause the helicoids to seize turning and this is just one of the reasons why you see some examples of this lens being sold for little money. Couple that problem with an oily iris and you get a junk that you can buy for less and you now have a project. The CRC unit is actually a part of the objective and that part is positioned too close to the iris assembly. Nikon initially used a light, runny grease for it and over a period the grease would creep into the iris assembly resulting in oily aperture blades. This can be avoided by properly storing the lens but it happens often because of the design so Nikon decided to use a thicker, more viscous type of grease to help negate this problem on later production lenses.

Let’s now see how this lens performs. Knowing how your lens performs is important for maximizing its use. You’ll know its strengths or weaknesses and that knowledge will be a big help so you’ll know what to avoid and how to use the lens’ flaws to your advantage in creative ways that will help make your pictures unique. I took these photos using a DSLR and I shot these from f/2.8, f/4 and f/5.6 in that order from left-to-right. In these apertures, you will see the most changes in this lens’ rendering characteristics so I use these for the examples. Everything looks similar from f/8 on in terms of rendering and all you will see are improvements in sharpness until you reach f/16 where you’ll see diffraction come in. Stopping the lens beyond f/8 also increases depth-of-field and this is the primary reason for stopping this lens down past its optimal aperture numbers. The performance of this lens peaks at f/5.6 in terms of resolution and about f/8 for sharpness, do remember these aperture settings when you need the best sharpness and resolution in your pictures.

(Click to enlarge)

You get some vignetting wide-open but it improves by f/4. It’s gone by f/5.6 mostly and it’s only slightly-visible if you look for it. This level of vignetting is not so bad and you’ll not notice it much in real-world pictures unless you shoot something like the sky or an even-colored background like a painted wall.

_HAW6621Here’s a preview of how the quality of the bokeh looks like. I intentionally took this photo because twigs and leaves are handy for revealing bad bokeh quality. It’s smooth as far as I can see and you don’t get the ugly smudging and hectic-looking bokeh that foliage cause. This is good news because macro photography demands a smooth background. I used to take plenty of bug photos and nothing makes the background worse than bad bokeh.

FH000030This is probably the worst that I can get this lens to exhibit some bokeh smudging. I think I took this at about f/5.6 so the blurring effect isn’t great. Despite the slight smudging, this still looks smooth and isn’t severe at all compared to what you get from other lenses. This effect is caused by a lens that’s over-corrected for sharpness if I am correct and is typical of many early Sonnar copies from the rangefinder camera era.

(Click to enlarge)

The lens is sharp wide-open but the thin depth-of-field makes it appear soft. Resolution is not the best wide-open and this also contribute to this. Everything improves drastically if you stop the lens down to f/4, the resolution is good but it will improve once you stop the lens down to f/5.6 where it reaches its peak performance. Chromatic aberration is seen in small amounts but it’s not a big problem at all. The quality of the bokeh is nice wide-open and will remain to be smooth at f/5.6 when shooting really-close. The last set shows how the lens performs when the lens is focused further. It mirrors the results that we’ve seen in the previous sets except that it’s better in the close-up pictures. This isn’t saying that it is bad, it’s just that this lens was optimized for macro-ranges. You also need to remember that this lens was in bad shape when I got it and that will also affect my results so do not take the results from this simple test as the absolute truth.

_HAW6618This picture is nice for showing the effects of chromatic aberration but I cannot find that here. The best way to show this effect is to shoot shiny metal objects and look for them at the shiny highlights. The sharpness is good so far and the background is so smooth. This was shot wide-open so the depth-of-field is shallow.

_HAW6619Another photo shot wide-open. The thin focus plane makes positioning your subjects and the other elements in the scene difficult. Luckily for us the field curvature isn’t deep, this makes it easy to visualize the focus plane in your head or see its effects in the viewfinder. See how nice the stamen is? It’s going to get much-better when you stop this down to f/4. I like this rendering a lot and it has a slight painterly-look to it.

_HAW6620Here’s another photo that was shot wide-open. The background just melts into a smooth wash of color in this picture. The rendering of this lens looks natural unlike what we get mostly these days from over-corrected lenses because pixel-peepers demand high scores over a lens’ rendering characteristics and other things that you can’t measure. While it is true that macro lenses should be the pinnacle of sharpness when it comes to lenses, what is equally true is that lenses are artists’ tools and they should be judged as such.

Let’s see how this lens performs with film. Film renders differently from digital so it will be beneficial for us to study how a lens work with both mediums, only then can we get a good grasp of a lens’ performance. This lens was designed during the film era and seeing how it works with film brings us closer to its essence for the lack of a better term. I’m not a purist, I just enjoy using my lenses in their historical context to study them better. This is what makes this site different from the rest because you get to see how a lens works in both film and digital on real-world subjects. I used Fujifilm Industrial 100 for these and I had them scanned using Fujifilm Frontier SP-3000, the best in Japan.

FH000001Here’s our traditional Tom Sawyer photo. The subject separation is great, almost 3D. This should quality is missing many lenses today and this is why I shoot older lenses recently. The background is blurred beautifully, almost like a Bob Ross painting or the background in the movie Bambi which was inspired by the traditional school of Chinese painting.

FH000006The thin focus plane wide-open is evident in this photo despite the subject being around 5m away from me. If you have a keen eye you’ll notice traces of chromattic aberration in the 2 metal dampers at the front of Thomas’ red base. It isn’t bad at all and you won’t see it unless you looked for it. The focus is on the round ports, I missed Thomas’ face because I have hay fever and my eyes were itchy.

FH000028This was shot at f/5.6, I think. This is the merit of this lens family, not only are you able to shoot close-up photos with them you can also use them for general photography. It’s nice as a walk-around lens because of that, I even saw John Free using the same setup on one of his YouTube videos. He had a Nikon F3 and this lens with him on that video. The guy is just as legendary as this lens, do check him out if you haven’t heard of him.

(Click to enlarge)

Some more pictures where the subjects are about 10-20m away from me. It’s great using this lens for general photography because it’s still considered a normal lens. Actually, the 55mm focal length is closer to how the human eye sees things compared to a 50mm lens. The 58mm class of lenses is the closest one, try viewing through one on a camera that has a 100% view coverage and high magnification that’s more than 0.8x and open your eyes to see how it feels like. The fact that this lens is sharp is just a bonus.

(Click to enlarge)

Now for some things that are closer that 1m or so. The low geometric distorion makes the photos look natural. We can sometimes sense that an image feels a bit off just because it has a hint of distortion. I know some people who are sensitive to this, I don’t know what’s causing them to pick it up more than the usual people but they have an eye for this. I am a person who wears glasses, maybe that hinders me from detecting that, too?

FH000015I think this was shot at f/4 or f/5.6, just look at how good the details are on the flower. The background also looks exquisite, complementing our subject. You can even see the pollen dusts individually, reproduced in great detail despite me using a cheap film. This is what I meant by peak resolving power, you will be able to see small details like what we have in this picture clearly and not blurred in any way (when focused).

FH000002A very natural-looking photo of flowers! The droplets look sharp, juxtaposed against the velvet-looking petals of the pansies. The Nikon F3’s center-weighted is great for this since it’s biased-heavily towards the center of the frame.

(Click to enlarge)

Some more pictures along the same theme. This lens is great for taking pictures of plants and their details for the reasons that I will explain in the last photo of this section. These were taken using various aperture numbers, can you guess which one was taken at what aperture? I know some people who like taking pictures of mushrooms, I don’t know why they like shooting them but this lens will be perfect for that purpose.

FH000031Wilted sakura blossoms. Despite being shot at about f/4 or so, the depth-of-field is thin so you will want to stop the lens down to around f/8 or more if you want to get the blossoms at the back to be in focus.

FH000009Finally, a photo that should give you a nice idea of how this lens works for taking photos of small inorganic objects like in a product photography setting. The 55mm focal length is ideal for this purpose because it’s not too long to make the subject look flat or smaller but it’s not too wide as to distort the subject, making it look larger-than-life or distorted. I like this natural perspective, it hits the focal length sweet-spot perfectly.

(Click to enlarge)

I can recommend this lens to anybody who wants a lens in the normal range but can also focus close for detail shots. This will be perfect for wedding photographers who needs to have a lens that can serve as a normal lens and one for taking shots of the ring. If you’re taking pictures of bug and you want to be able to shoot in life-size magnifications this is not the lens for you because the tip of the lens will have to be inches from your subject to get to that magnification ratio. This will scare your subjects or just get in the way of your lighting unless you use a ring flash setup. If you have a studio then this won’t be an issue for you and you can even use this lens for shooting a series of pictures for focus-stacking. You will want a moving platform or those fancy servo-operated gadgets for this. You can also use the helicoids and rack you focus so long as the magnification isn’t great, this will work if you’re taking photos of flowers or larger objects since the depth-of-field is wider if you’re not focusing really close. Before I get too deep into the technical points of macro photography, let’s end this introduction with a few pointers. If you want to buy this lens, make sure that it doesn’t have an oily iris and the check if the helicoids are smooth, light but damped and not stuck. These 2 are the most common issues of this lens and majority of the cheaper ones you see online have this problem. I will say that it’s better to spend a little bit more and get an excellent copy because repairs aren’t cheap. With that said, you can never go wrong with this classic.

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. Please also read what I wrote about 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 novice. Before opening up any lens, always look for other people who have done so in Youtube or 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 (CRC Unit):

This lens is one of the more complicated ones in this blog as far as smaller Nikkor primes go because it has CRC and a more unconventional construction that’s typical of most Ai-S lenses because they were made in an era where Nikon was experimenting with ways on how to make their lenses lighter, with less parts and more compact. This means that our traditional sequence of removing the objective first and working on barrel separate from the optics pattern won’t be applicable for this and most smaller Ai-S primes. It also uses a few clever engineering tricks that you should watch-out for if you’re a novice so don’t be careless and impatient when working with this lens.

This section can be broken-down into several parts:

  1. Focusing unit/main lens body
  2. CRC unit
  3. Objective/lens assembly
  4. Iris assembly

I’ll outline this tear-down in a similar manner to make it more manageable and easier to read or else it will be a long and jumbled mess. You can choose to start in any order as in the case of repairing the iris assembly only and leaving the helicoid overhaul for another day or situation but you will still have to follow certain steps and this article should be a big help for those who are not familiar with Nikkors.

IMG_1516Carefully remove the screws securing the bayonet mount to the lens. If you are new, read my article on removing bayonet screws. These screws are special and you’ll need a driver that will fit them perfectly. Many beginners strip these screws because they used philips drivers or they didn’t use the proper technique. This is the reason why many people get stuck at this stage and ruin a lens. Carefully follow my screws article so you won’t strip your screws.

IMG_1518To remove the objective’s housing remove these 3 screws. Be sure that the lens is focused to infinity when you do this and avoid turning the focusing ring since this is going to be your reference point.

IMG_1520Carefully remove the objective and make sure that you do not knock or turn any part of the assembly. This lens has CRC and it’s a precise adjustment so you would want to know how things were aligned and by how much. Do this step this while keeping the focusing ring set to infinity. The objective is heavy and it may drop and dive into the floor if you are not careful so always be careful with this.

IMG_1538I marked most of the important alignments when this is focused to infinity. This includes the helicoid stop for the CRC unit (encircled) and the midline of the lens. You can also try another method, measure the gaps and remember them for reference.

IMG_1539Remove these 3 screws to separate the iris assembly from the rest of the objective. One of the screws might be obscured by a lever just like in the picture above so you may need to turn the lever to access it. Note that the 3 screws are gone in the picture. Just take a look at that fungus, Yuck!

IMG_1540Carefully separate the iris assembly from the objective and be sure to keep things aligned while doing this. You may have marked these previously but you want to be careful since CRC can be a pain to re-align later. Just take a look at all that dirt!

IMG_1541.JPGTo separate the CRC components you’ll have to first unscrew these and remove the key to split the tiny CRC helicoids.

IMG_1542Separate the CRC helicoids but be careful to mark where they separated. These is my own property so it’s OK to mark it like this but if this thing belongs to somebody else then you would want to make your marks smaller.

IMG_1543Remove the main CRC helicoid from the rest of the objective. Note how that notch on the brass ring should be before you remove it. Remove the brass ring to thoroughly clean it but mark where things should be aligned because this is the part that syncs the CRC unit with the rest of the objective as you focus your lens.

That’s it for the CRC unit. This is the trickiest part of this lens so you should take plenty of notes or pictures to help guide you later during re-assembly. Clean the helicoids well and apply a very thin film of fresh grease. Never apply too much because excess grease or oil can migrate to the iris later and you will have to do this all over again.

Disassembly (Objective):

The objective is probably the easiest part to work on provided that you have the correct tools and skills. Just make sure that you took plenty of notes so you won’t get lost later.

IMG_1544First, remove this part using a rubber plug to reveal the 3 little screws underneath it.

IMG_1545Unscrew these to remove the “hood” and be careful not to scratch the front element.

IMG_1546It should come-off easily. If this part was sealed then you should put a drop of acetone to soften the seal up and attempt it again after a few minutes. Just make sure that you don’t apply too much solvent because it may end up in the glass.

IMG_1547Just take a look at the fungus under the front element! By the way, I kept the screws there for safekeeping so please ignore the fact that they are there on this picture.

IMG_1549.JPGUse a lens spanner to remove the front elements assembly from its helicoid. I also had to apply some acetone to this part since it was sealed in place by lacquer. Sorry for showing a little bit of skin.

IMG_1550.JPGThe front elements assembly can be opened by removing the retainer ring that holds this thing together. Carefully use a lens spanner to open this thing and do not force your way when it is stuck as you might damage the front element. Just place a drop of alcohol and it should soften the seal.

IMG_1552The rear elements assembly is attached to the iris’ casing, it can be easily be removed by twisting it with your fingers. It can be further taken-apart by removing the retention ring that secures the rear element by using a lens spanner. That thing on the right is the front elements assembly.

IMG_1557Six-elements-in-five-groups, simplicity is best. The 2 retention rings are placed above for reference. You should mark the sides of each element assembly with a soft lead pencil so that you know which one faces forward when you reassemble your lens.

I got rid of the fungus using the method described in my popular fungus cleaning article. The fungus cause some damage to the coatings but the glass wasn’t etched, thankfully. It was simple to clean the objective and I also cleaned the housing of the elements because the spores are still there. I used the same soup that I used for cleaning the glass because I don’t want to throw that away as that would be a waste of chemistry.

Disassembly (Lens Barrel):

The lens barrel is easy to dismantle as it’s pretty conventional for an Ai-S Nikkor. Follow the same guidelines that I have for the other lenses and this should be easy. The helicoids for this lens are long and you should pay a lot of attention to them specially when you’re separating them.

IMG_1521I reoved these screws that secure the aperture ring to the aperture fork. Once the screws are gone you can safely remove the aperture ring. You will notice that the ring looks a bit moist, these things were sealed with lacquer so a bit of solvent was needed to make them easier to remove. Heating them with a soldering bolt helps, too. These are easy to destroy as they’re small, dainty and can be rusty at times. I have hundreds of these to replace the ones that are rusty.

IMG_1525The aperture fork can now be safely removed from the lens.

IMG_1524To separate the helicoids you’ll have to remove the helicoid key. Remove these screws so you can remove the helicoid key. These screws are notorious for being sealed using hard adhesives like epoxy. The safest way to remove these is to heat the screws with a torch, a small butane torch should soften the epoxy in no-time and unscrew these while they are hot. You don’t need to heat them until they glow red.

IMG_1526You can now safely remove the helicoid key from the lens body. Notice the white powder in the threads? That’s the epoxy that I am talking about. Epoxy has a distinct smell and it is easy to detect it once you heat it.

IMG_1527Now that the helicoid key is gone, you’re free to separate the main helicoid from the rest of the lens. Be sure to remember where it separates. Mine separated at this point. If you decided to remove the focusing ring before doing this then you should mark where they separated by scribing a line on the surface of the helicoid where it will not be seen or get into contact with another helicoid. If you are new to lens repair, read my article on how to work with helicoids. Many people get stuck because they can’t put the helicoids back, I don’t want you to fall into the same problem that’s why I’m spending a lot of time on this blog to help you.

IMG_1529Carefully remove the rubber grip by sliding a small, thin screwdriver underneath it and run the screwdriver on the whole circumference of the rubber grip to lift it. Don’t tear a hole while you’re doing this, the rubber can get brittle and break if you’re not careful.

IMG_1530Once the rubber grip is gone you can now unscrew the front part of the focusing ring. It’s thin so you do not want to warp this part because if you did you will end up with a rough focusing lens as this part will rub against the front barrel when you focus. You can also remove this part while the rubber grip is still attached if the rubber grip itself isn’t being held by any adhesive. This is preferable since you do not risk tearing the rubber grip. You should probably try this first and see if it works.

IMG_1531There are 3 screws in the focusing ring that hold it to the main helicoid. These screws are also used for adjusting your lens’ focus so you would want to remember where they are originally before you remove them by marking their respective positions. If you messed up, you can simply adjust this later. The group of 3 small screws encircled in the picture is used to secure and adjust the helicoid stop. You can usually overhaul your lens while leaving these alone. These are positioned precisely so that your lens can achieve infinity focus so leave these alone if you can help it.

IMG_1533You are now free to remove the focusing ring from the main helicoid.

IMG_1534This is the best time to remove the inner helicoid from the main central helicoid. Be sure to mark where these separate.

IMG_1536For a thorough cleaning job, remove the chrome grip by unscrewing its screws. With the chrome grip gone, you can now remove the sleeve by carefully twisting it using a rubber glove. Nikon at times glue the metal sleeve to the main barrel with lacquer so be patient and put acetone at the seams if the sleeve will not come-off the first time around, repeat it until the glue is soft enough and try it again. I advise cleaning this since grease usually finds its way under this metal sleeve.

That’s it for the easiest part of this article. I cleaned the helicoids very well and applied a lighter type of grease. A heavier type of grease will just make focusing difficult because a lot of torque is needed to turn all 3 helicoids in the barrel plus the small once used in the CRC unit. The helicoids are also on the long side so there’s a lot more surface area that’s touching each other when you turn the helicoids. Make sure that you don’t apply grease excessively or that may end up in the iris.


This was a fun lens to repair but I wouldn’t consider it easy because of the CRC unit, with proper guidance and tools a novice will be able to overhaul this properly without trouble at all. I didn’t clock myself but I can say is that it will take you several hours, maybe even a whole day if you consider overhauling everything including the ball race assembly on the bayonet mount. Before you put on the finishing touches, here are some things you’ll have to consider.

For many people, the reason why they would want to read this tear down is because they need to clean up the oily aperture blades on this lens. This is a common problem for the Micro-Nikkor 55mm f/2.8 Ai-S lens but is easy to prevent. Many people will just open up this lens to access the iris assembly to clean it and then put the clean iris assembly back into the lens and assume that it will work again without any problems. While this is fine for most cases, you would want to clean the root cause of the problem which is the oily helicoids so it is advisable to just do a full overhaul of the mechanical components of the lens. A lazy repairer will only cause you to lose more money in the long run.

I didn’t need to clean the aperture blades on all of the Micro-Nikkor 55mm f/2.8 Ai-S that I have fixed so far, so I did not take any notes. It is not difficult to do at all but if you need to clean yours then just head to this YouTube video from the master himself and see how he overhauled the iris assembly.

Update: I had to clean the iris of a friend’s lens but I didn’t take any photos.

IMG_1551Be sure to apply a little nail polish to both ends of the spring to secure it. A small amount goes a long way so do not apply too much.

IMG_1554To adjust your lens when it fails to achieve infinity focus, reassemble your lens but leave out the front parts so you can still adjust these screws on the focusing ring until you can achieve infinity focus. Once you got it right then you can finish reassembling your lens. If you are not sure how to adjust your lens, read my article on infinity focusing calibration. This should help you understand the basics of how this is done in a DIY setting.

Finally, do not forget to lightly lubricate the slots and canals of the helicoid keys for both the main one and for the CRC unit. If you forgot to do this then you might end up with a squeaky lens. Don”t over-lubricate this or youll end up with oily aperture blades. A little goes a long way as far as lubrication is concerned.

Once overhauled, this lens will last you many many years of use, manual focus lenses are built tough compared to what’s being produced these days. If you used the correct grease and did not put too much of it then the aperture will never get oily again. Just remember to always store this lens facing up so gravity will force any excessive oil to drip down, not towards the iris assembly.

I hope that you have enjoyed this post. It was rather long and it took me around 5 nights to write this since the lens is a bit complicated. If you have benefited, enjoyed or learned from this post then please do not forget to share or click on the ads on this page. This will help me a lot in terms of maintaining this blog and keeping this going. You can also opt to support this page and any help is welcome, it will help me with buying, developing and scanning film for the reviews. My contents are original and I try my best to give the best quality content that I can using my knowledge in photography and repair and your help will make sure that this conitnues. Thank you very much, 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.

58 Comments (+add yours?)

  1. Ron V.
    Feb 23, 2016 @ 20:21:12

    Again…………….excellent work Rick, much appreciated.
    These lenses are well known for having helicoid issues………….mainly the grease solidifying over time.
    This article has given me the encouragement I needed to pull my sample apart.


    • richardhaw
      Feb 24, 2016 @ 02:54:21

      Thanks! this is not difficult to be honest. a 55mm is probably one of the first lenses that i took apart. (1st one was a Sigma super 24mm from the 80s). I am thinking of adding some exotic lenses like the GN and the 5.5cm f/3.5 here because their engineering is just so different from what you usually see from Nikon!


  2. Angel
    May 10, 2016 @ 14:00:56

    Excellent guide Rick. I just bought a cheap 55/2.8 with stuck iris so im about to follow your guide.


  3. richardhaw
    May 28, 2016 @ 14:07:31

    Hello, Angel!
    Sorry for the late reply. The aperture not closing may be a sign of oil in the aperture blades. I do not understand what you mean by the DOF pin.


    • Angel
      May 28, 2016 @ 19:12:35

      I meant the aperture lever but later i found that its normal on some versions. Today i tested it and this lens is wonderful!


      • richardhaw
        May 29, 2016 @ 00:07:47

        Hello, Angel.
        I am not sure about that, it should spring back all the time when the lens is assembled. the lens is amazingly sharp. it is also very useful as a normal lens. Ric.

  4. dfgriff57
    Aug 09, 2016 @ 16:51:58

    Hi Richard, I went through you’re procedure and all is well but for one tiny thing that I can’t figure out. I removed the rear lens elements for cleaning but upon assembly, it looks as though the two elements touch each other when I tightened the outer retention ring. I didn’t notice this at first so it could have already been like this. Are there any shims or other spacers in the rear lens group besides the one you show? Thanks again for making tutorial, helped a bunch


    • richardhaw
      Aug 10, 2016 @ 00:35:24

      Hi! Sorry but I do not remember that part of the lens very well. Are you sure that what you heard is the apex of the lens coming in contact with each other? Or is it just the sides. be careful as you might break the glass. Ric.


      • dfgriff57
        Aug 10, 2016 @ 00:49:58

        Hi Ric thanks, yes it is making contact. I can see a sort of spot forming right in the middle as I tighten the retention ring. If I leave the ring slightly loose, the center of the lens remains clear and the images I make are sharp. If I tighten the ring hand tight, the spit appears and images have a fuzzy look in the center. Guess I can save it as a paper weight. Thanks again.


      • richardhaw
        Aug 11, 2016 @ 13:58:30

        Hi, sorry for the late reply. I am quite busy these days. You have to be careful as you may have the rear elements in the wrong order/direction. I am not sure but this is a very common mistake. Ric.

  5. Trackback: Internet Nikon Repair Resources – My Take on Photography and Diving (Underwater Photography Mostly)
  6. Chris_R
    Jan 06, 2017 @ 11:38:50

    Great article, thanks. Do you have a recommendation for lube for the outer main focus helicoid? I have a couple which have gone stiff (105 the same).
    I’d better buy a screw extractor kit – insurance!


    • richardhaw
      Jan 14, 2017 @ 14:06:21

      Hello, Chris! Sorry for the late reply. I tend to use the same grease for the whole lens to avoid mixing the grease’s chemistry and foul up the helicoids as time goes by. I use a thin type of grease sparingly to prevent the grease from migrating into the iris. Ric.


  7. Trackback: Repair: Micro-Nikkor 105mm f/2.8 Ai-S | Richard Haw's Classic Nikkor Maintenance Site
  8. Michael. Cutini
    Jul 30, 2017 @ 01:21:54

    Hi Ric, Thanks for the good info. and good looking pictures. I wish I’d seen this site before I took my lens apart.I’d only found one for removing and cleaning the aperture.This aperture was fine but the focus ring took Superman to turn. So I disassembled to the aperture and then kept disassembling. But I marked nothing. (Live and Learn). I cleaned and greased lightly (using a silicone brake parts grease from an auto parts store). Now when I reassemble the two CRC components making up the front lens assembly (one R.H. threads, one L.H.), they turn nice and easy until I reinstall the piece held by two screws with projection on it that goes into a slot. The projection has a slotted screw in it. Then it locks up tight. Any suggestions? (I don’t know what anything’s called except what I’ve on this and one other post). Thank You, Mike


    • richardhaw
      Jul 31, 2017 @ 08:20:52

      Hello, Michael.
      I am not sure what you really mean but if you read my article, I remember mentioning that I use a lighter grease for this lens because it has so many helicoids. Ric.


      • Michael. Cutini
        Jul 31, 2017 @ 19:28:52

        Ric, Yes, I read that. This silicone grease and so little of it cannot be the problem. Even when everything’s clean and no grease it positively locks. Can I send pictures to show the problem? Mike

    • Norman
      Sep 28, 2017 @ 17:41:08

      Michael, I think you are referring to the cam follower on the CRC, if so it is meant have this apparent effect so that the front element group rotates internally causing it to move back and forth.


      • Michael
        Oct 02, 2017 @ 02:55:13

        Thanks Norman for the info. Fortunately I got this back together and working fine just last week. After weeks and an awful lot of deliberation and talking to myself (should I just toss it?, I wanna keep it – it’s so good, etc., etc.) Mostly from seeing pictures online. This site and others. Mike

      • richardhaw
        Oct 04, 2017 @ 09:56:11

        this lens is a keeper

  9. Trackback: Articles Index | Richard Haw's Classic Nikkor Maintenance Site
  10. Trackback: Report: Nikon Fan Meeting 2017 | Richard Haw's Nikon Maintenance Site
  11. Norman
    Sep 28, 2017 @ 18:02:03

    Richard, I noticed that the two screws holding the back and front of the aperture assembly together go through slotted holes and that, though its fiddly, this allows adjustment of the aperture at 2.8 so it is fully open on the click stop as opposed to being slightly closed and only fully open when the ring is moved slightly/fully past the click stop. Not important but interesting, maybe other lenses are similar.


  12. Trackback: The Nikon Cameras Used by NASA | PictoPro
  13. Trackback: The Nikon Cameras Used by NASA – Photography News World
  14. Trackback: The Nikon Cameras Used by NASA – Get Photo Tips
  15. Trackback: The Nikon Cameras Used by NASA – PetaPixel (blog) | Deals to find
  16. Trackback: Repair: Nikkor-N 24mm f/2.8 Auto | Richard Haw's Nikon Maintenance Site
  17. Trackback: World of F-mount Nikkors (2/3) | Richard Haw's Nikon Maintenance Site
  18. Trackback: Shopping: Matsuzakaya Camera (Shinagawa) | Richard Haw's Nikon Maintenance Site
  19. Trackback: Repair: Micro-Nikkor 105mm f/4 Ai | Richard Haw's Nikon Maintenance Site
  20. Trackback: Repair: AF-Micro-Nikkor 55mm f/2.8 | Richard Haw's Nikon Maintenance Site
  21. Bruce
    Jun 05, 2018 @ 00:22:56

    Thank you very much for your great repair tutorials! I have a little different problem.
    My 55mm F2.8 Micro Nikkor focuses to 30m, but not to infinity on my D300 when I manually focus to infinity. What steps should I take to fix it? The lube and iris are in great shape and do not need work. Thanks.


    • richardhaw
      Jun 21, 2018 @ 16:06:59

      I remember mentioning in the site that site for the 55/2.8 that the helicoids need to be reset properly. If you read and saw my video, I showed a way there for guessing where the helicoids should mate. The article also showed how to adjust the focusing scale of the lens. Ric.


  22. Branly
    Jul 29, 2018 @ 13:15:33

    Hi Richard
    I could revive one 55 mm aperture that was stuck easily because screws had already been removed.
    I bought another one that has a very good aperture but focus was difficult . I regret I destroyed 2 of the 3 screws of the bayonet . Then tried to dril it and destroyed the bayonet !
    So I can remount only 2 of the 3 screws. Do you know where I could find just the bayonet ?
    Then internally several screws broke ( no chance)
    So I bought a cheap new 55 mm in which Just the aperture is blocked.
    Do you have any spare screwdrivers and screws before I made again stupid operations ?
    Regards from France


  23. Branly
    Aug 10, 2018 @ 11:37:50

    I received my Brand new screwdrivers from Vessel as advised in those tutos
    But it is impossible to remove the 3 screws from the bayonet . I even tried to heat the screw with à solder iron to brake the epoxy .
    Now the 3 screws are already destroyed … and I ca not put any torque

    What the solution ? Destroy the screws with the risk again to let them in the body
    Any other ?
    In any cases I will need new screws
    Please help


  24. Bjørn Solberg
    Aug 16, 2018 @ 22:16:15

    Hello Richard,

    Thank you for sharing this very interesting article!

    I have recently purchased a very nice copy of the Nikkor 55mm f2.8 Micro. Unfortunately there is some contaminent on the lens surface facing the aperture blades of the rear lens element group. Is it possible to remove the rear lens element group with i.e. a friction torque, without removing the bayonet?


  25. Fabien
    Mar 30, 2019 @ 11:21:57

    Thank you very much for this great tutorial. I am being repaired from my 55mm. I totally dismounted it. No problem for the re-assembly of the diaphragm part but I am now stuck with the re-assembly of the parts of the focus ring. Do you have a little tutorial to help me? Thank you and sorry for my poor Englishman. Fabien


  26. Trackback: Repair: Nikkor 28mm f/3.5 Ai-S | Richard Haw's Classic Nikon Repair and Review
  27. Trackback: Repair: Micro-Nikkor-P 55mm f/3.5 Auto | Richard Haw's Classic Nikon Repair and Review
  28. Xovercameras
    Oct 21, 2019 @ 08:15:43

    Hi Richard,
    Awesome article thanks. Bought a bunch of old Nikkors for a bargain but all had fungus and the 55mm Micro was also jambed on all the helicoids. Followed your procedure and managed to get it perfectly clean and functioning. Had a few issues fixing the objective to the body as the objective was moving okay till I fixed it in position. After 4 goes I then realised that I was clamping it hard on infinity. So slackened the screws, moved the focus a bit and retightened to the body and it works well. Bit of locking right on infinity but that is set okay. Did a test on a Sony Nex and I cannot believe just how good the clarity of the infinity shots from such a small lens. I need to do a better clean on the helicoids as still a bit sticky but it is a great result so far. Looking forward to using it on my old film Nikons. Cheers. Robin.


  29. Trackback: Repair: Micro-Nikkor 5.5cm f/3.5 (1/2) | Richard Haw's Classic Nikon Repair and Review
  30. Trackback: Repair: Micro-Nikkor-P.C 55mm f/3.5 Auto | Richard Haw's Classic Nikon Repair and Review
  31. Trackback: Repair: AF Micro-Nikkor 60mm f/2.8D | Richard Haw's Classic Nikon Repair and Review
  32. Trackback: Repair: Micro-Nikkor 5cm f/3.5 (LTM) | Richard Haw's Classic Nikon Repair and Review
  33. Jeff Brewer
    Sep 06, 2020 @ 12:59:00

    Hello Richard,
    Thanks for this article. It saved me and this AI 55 2.8 Micro lens.
    As a first foray into the world of lens repair, I found your wealth of practical hints a priceless asset. I will augment your two dollar request with another ten. Have two cups of coffee!
    I took the bayonet-screw comments seriously and went straight to using my ox-acetylene micro jeweler’s torch to heat them. That worked great. Your advice about Vessel screwdrivers is spot on. They are a total pleasure to use, and I had no problems with screws whatever.
    Perhaps you should mention somewhere that the word helicoid starts with “hell”.
    Also, if I had followed your advice about copious notes I could have saved about an hour of time during re-assembly.
    I have a new appreciation for Nikon and I am loving using this lens. Thanks again.


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: