Repair: Nikkor-S.C 55mm f/1.2

What’s up, everybody? I am loving the weather now because Spring is nearly here! Here in Japan, we will celebrate the Spring Equinox next week. I’m sure glad that the seasons come and go every year. Speaking of cycles, there are times when I would service a lens and feel I have worked on something similar to it before. This is one of those, read on.


I would like to introduce to you the Nikkor-S.C 55mm f/1.2 lens! If that sounded familiar to you long-time readers it is because this is the predecessor of the New-Nikkor 55mm f/1.2 lens that we have tackled a little more than a year ago. This lens is exactly the same as its successor optically but the focusing unit (lens barrel) is of the earlier Auto-Nikkor era look. I personally like the vintage look and the all-metal construction of this lens. I was actually looking for something similar to this lens but with the Ai update but I have different sets of priorities lately so I will forget about hunting for this lens for now.

img_2697Here is the Nikkor-S.C 55mm f/1.2 together with the New-Nikkor 55mm f/1.2 lens. You can say that the later lens is simply a cosmetic update of the earlier one and I would agree with you on that observation. They both handle the same, which is excellent.

This lens isn’t mine, it came from one of our readers who wanted this lens revived because this is one of his favourite F-mount lenses. It is very well-used as you will see later during the dismantling section. I normally turn-down any requests but I’ll sometimes accept the request if I am in the mood, specially for the sake of this blog. You know that I love you.

img_2623Just take a look at that beautiful front element! Initially, I thought that the lens coating is in bad shape because the highlights showed some irregularities as evident in this picture. I wiped it off and found out that it’s just some disgusting oil. Yuck!

Since the lens wasn’t with me for a long time, I didn’t use it to take much photos. Photos that I took with this lens are more for focus confirmation purposes than anything else. All of the sample pictures above came from the owner of this lens. As you can see from these beautiful pictures, the owner really used this lens a lot. His pictures show a wide spectrum of things that this lens is capable with. You can see that it also has the double bokeh effect or 二重ボケー as what we call that here in Japan but some people actually like it and treat it as part of the unique character of this lens. This is a subjective topic so I will just leave it here. I personally prefer it at times but I would love to have it at times.

The lens is capable of taking sharp photos on a 14MP digital sensor even wide-open but It will show its limits when it comes to 24MP sensors and above. The resolving power of this older lens simply wasn’t built for the higher MP sensors of today; nobody pixel-peeped in the film era! I even argued with the owner about the performance of his lens so I tested my own New-Nikkor 55mm f/1.2 lens and found the same to be true with my copy. I will write a study about this phenomenon when I am not busy. Some people say that MP count has no effect on what a lens can deliver but this test should prove that wrong. Stay tuned.

For a more in-depth write-up of this lens, please check out the New-Nikkor 55mm f/1.2 lens write-up because this is optically the same as that lens. Now, on to the dismantling!

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.


This lens is typical of Nikkors of the same era so it’s pretty standard. If you have been doing this for some time then this is going to be routine for you. This can be an ideal project for beginners with some experience and understanding of the fundamentals of lens repair and maintenance. Always read my primers, there is a reason why I post that on every teardown that I make so I hope people just do not browse past that part.

Experienced or not, I will warn you to be careful with this lens because the glass is heavy. I almost dropped mine a long time ago due to slippage! It is also big and exposed so be very careful not to accidentally scratch it.

The lens was sent to me with the request to overhaul the focusing unit and clean the dirty lens thoroughly. The optics are clean so it is best not to bother with it. I did find some fiber and dust inside of it so I got a blower and blowed away what’s in there. Having mentioned that, I will not be working on the objective this time so if you want to work on yours then I would highly suggest reading my blog post on the New-Nikkor 55mm f/1.2 because that lens is similar to this in many ways.

img_2668Such a lovely lens, unfortunately it’s very dirty! I will need to thoroughly clean this. There are lenses that are best accessed through the back and there are also ones that are easiest to work from the front. Lots of Ai-S lenses fall on the former while earlier Nikkors usually belong to the latter. This is an early one with a metal ring so we will not do a “rear entry”.

img_2669Begin by removing these 3 screws. These big screws secure the focusing ring.

img_2670Once the screws are gone, you can get rid of the focusing ring. These are sometimes glued or old and cakes grease might have fused with it, acting like a glue of some sort.

img_2671Once the focusing ring is out of the way, you can remove the small set screw found on the front ring. The set screw secures the front ring and makes sure that it doesn’t move. Once that set screw is removed, store it in somewhere safe so you won’t lose or damage it since it is so small and delicate. The front ring can be screwed off just like that after that small screw is gone. Be careful not to dent or warp the ring since it will affect your focusing ring.

img_2672The front ring secures the objective so never point the lens down or it will drop to the floor! That brass ring that you see in the picture is used to calibrate focus so do not lose this. You see that slot on the front helicoid’s tip? That slot is where the screw found in the objective is supposed to be aligned. It keeps the objective in place and prevents it from turning inside the lens.

Pull the objective out from the lens barrel and keep that somewhere safe. Be careful not to leave the objective standing on either end on a hard surface or you will risk scratching that delicate glass. The best way to store this is have it laying on its side but be sure that it will not roll over and drop to the floor.

img_2673Now that the objective is out of the way, we can safely work on the rest of the lens without worrying about scratching anything on the glass. To further disassemble the focusing unit, remove these 5 screws in the bayonet. These things may be glued and if they won’t move then you should place a drop of acetone/solvent on each screw and wait for it to soften the glue. It may take several tries before they will be soft enough for you to unscrew them with a JIS screwdriver. Alternatively, you can use a mini butane torch and heat the heads of the screws and unscrew them while they are hot. I don’t usually use this method because it can be dangerous if you accidentally burned the lacquer paint of the lens or worse.

Just make sure that you are using a JIS screwdriver with the longest shaft that you can find and use the power and weight from your forearm to unscrew these screws. If you stripped the head of the screw then you are done and you will require more expensive tools just to remove the bad screw. Many people quit at this point so be careful.

img_2674Once the bayonet screws are gone, you can remove the bayonet mount from the rest of the lens. There’s nothing connected to it so don’t worry.

img_2675Before remove the aperture ring, you should remove this screw first. This screw serves as a pin that connects the aperture ring to a mechanism inside that controls the iris opening.

img_2676Never attempt to remove the aperture ring while the screw is still there or you will damage it. You can safely remove the aperture ring at this point. Look at all that disgusting stuff.

img_2677Before we can access the helicoid key we should remove the chrome grip. The chrome grip and its sleeve protects the helicoid key. Remove these 3 screws so we can get rid of it.

Take a look at the chrome and you will see deep scratches on it. These scratches came from the focusing ring. The focusing ring is loose it wobbles about and scratches the surface of the chrome sleeve. The focusing ring was left like this for too long so this happened.

img_2678The chrome grip can be removed by pulling it away towards the front.

img_2679These screws secure the helicoid key. The helicoid key keeps the helicoids in sync as you turn the focusing ring. Remove these 2 screws carefully. Again, notice the dirt.

img_2680This is the helicoid key. Do not forget which side should be facing up or down later during reassembly! I always take a picture just in case.

img_2681I always do this with helicoids. I turn them until they are fully collapsed and I make a mark that corresponds to that position. This mark will help me confirm if I got the helicoids in the correct way during reassembly. If this is off then something is wrong. The position of this mark may not be the same after reassembly and that’s because the helicoids are now clean so there is more space for the helicoid to turn. It shouldn’t be off by more than 1mm.

img_2682Having made all the relevant marks, it’s now time to separate the helicoids! I always mark where they separate. Mine separated exactly on this screw and it corresponded to the line that I made for the centerline of the lens (above the helicoid key slot).

img_2683To separate the inner helicoid you must first remove this helicoid stop by getting rid of the 2 screws. This prevents the focusing ring from going past the lens’ focusing range and it’s in the way so the inner helicoid cannot be separated from the central helicoid.

img_2684Here it is. Do not forget which way should be facing up as this is not symmetrical!

img_2685And here is where they separated. Without these marks I would have no idea where I will mate these 2 together. It’s a pain guessing the right configuration so never forget this.

img_2686Brushing away the old grease reveals the nice thread underneath it. I will pickle this in an alcohol bath overnight to clean it even further and finally use a Dremel to further polish or remove any remaining residual grease to prevent contamination of the fresh grease.

img_2687To remove the stop-down lever mechanism and the aperture fork, you will have to remove this metal brace by removing these 3 screws that’s keeping it in place.

img_2688Next, carefully remove this spring using a pair of sharp tweezers.

img_2689Now, I wouldn’t bother cleaning the bearing because it’s annoying to put it back but since this lens is super dirty, I have no choice. To do that, you will have to remove this ring with a lens spanner and carefully use it on these 2 slots.

img_2690Before you remove the ring, be sure to place a shallow pan underneath it to catch any balls that would fall off from the track. It’s OK to lose 1 or 3 of these but any more than that will make this rattle just like Nikon’s early F-mount lenses like the so-called “tick mark” lenses

img_2691Here is the stop-down lever and its ring. The bearing makes sure that this part is smooth and responsive every time it is actuated. Later lenses tend to have a simpler mechanism to cut cost. For example, many Ai-S lenses have simpler mechanisms for this part.

img_2693The aperture fork can be removed earlier as soon as the metal brace is gone but I only got it out just now. Why? I don’t know. This is in charge of setting how much the iris will open if it’s actuated and it is linked to the aperture ring via the pin that we removed earlier.

That’s all for now! I know that this feels short when compared to my usual lens teardown articles but that’s really all that it took.


That was easy. I am familiar with this lens family since I have worked with it’s predecessor and the lens is of a standard construction scheme as far as larger Nikkor primes lenses are concerned. I would recommend this to beginners so long as you are careful with those big screws on the bayonet and that you be careful with handling the lens because of the huge and heavy objective. One careless slip and it’s bye-bye lens!

I would have taken the time to polish that huge scratch on the chrome grip but I wasn’t in the mood at that time and this isn’t my lens. It is not that polishing the chrome grip will damage it but it’s not a standard procedure as far as my workflow is concerned so I skipped it. Polishing scratches help conceal the damage but the downside is if you have polished too much and some parts of the aluminium alloy underneath the paint begins to show up.

Given the state of the lens and knowing how hard the owner uses his gear, I decided to use thread locking lacquer on all of the screws. I rarely do this but I do not want this Nikkor to go through any further damage now that it has been overhauled and cleaned. The damage that the loose screw on the focusing ring has caused a deep scar and I will do what I can to prevent something like that from ever happening again.

img_2695Wow, this is such an exercise! this is very time-consuming but it has to be done! My style is to press the ring on track and load the balls one-by-one like loading bullets to a clip. It’s going to take some time and you will fail many times but you will get it eventually.

Overall, the most time-consuming step of this whole project was the repacking of the ball bearing. I will normally skip this but I wanted to clean this to the best of my ability. It was also very cold when I worked on this lens so I do not want to spend too much time sitting on the wooden floor of my workshop. I have a space heater but that’s not enough.

img_2696The objective is pretty straight-forward. If you have been following my blog for some time then this should be easy for you. You can read my blog post on the Nikkor 55mm f/1.2 K as a reference if you think that will help because both lenses are very similar.

That’s it for this week! Please do check out these lenses, they are great so long as you know when and how to use the lens.  See you again in the next article and if you enjoyed this, do share and link to my blog. I do need the extra hits. I am doing better the past few months when it came to hits but I trust that we can do better by the end of this year. Thank you all for your support! The blog will not have been possible without you guys! 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.


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