Repair: Nikkor-H.C 5cm f/2 RF

Hello, my dear readers! I am currently occupied with last Winter’s backlog and I haven’t finished half of what I need to repair at this point. Most of it are my own stuff plus some belonging to my friends whom I do favors for occasionally. I am also occupied with the blog more and more these days as evident by my continuous posting in the past couple of weeks. I get my energy from the simplest of things like looking at pretty girls, visiting the camera bazaar with my baby or simply eating some good comfort food. Speaking about simplicity, I will be showing you today a very simple lens from Nikon that harks back to her formative years. It is a significant lens historically but has been forgotten by many due to it’s modest properties and abundance. Please sit back and enjoy the article.


The lens we are going to talk about this time is the Nikkor-H.C 5cm f/2 (RF) lens! This lens was conceived during war time (against the Republic of China) and throughout WW2. It was a lens that was partly designed during the designer’s free time at Nikon (known then as Nippon Kogaku K.K.) but went into production when Nikon shifted priority from usual military-related optics to consumer ones after the war for Leica and Canon cameras and eventually on Nikon’s own camera – the Nikon I. This lens represents the transformation of Nikon after the war. From a company manufacturing equipment for battle to one that makes products that bring joy to many people, including me.

img_3489You can think of the Nikkor-H.C 5cm f/2 as a kit lens of some sort as it is usually sold with Nikon’s rangefinders. I am not sure if this was sold like that straight from the factory but I’m guessing that it was since Nikon’s rangefinders have an internal helicoid for the 5cm class of lenses. Here is mine with my Nikon S2.

The lens began it’s life around 1935, was completed at the middle of the WW2 in 1942 but the design was finally perfected in 1948 when the supply of (rare) raw materials for glass manufacturing stabilised. This halted the need to adjust the design ever so slightly just to accommodate the different qualities (index of refraction) of the materials used.

IMG_3598Look at all that oil on the iris! It’s not so bad here and I find this to be tolerable but there are cases when the oil is worse than this and that should require a complete overhaul!

The Nikkor-H.C 5cm f/2 was of a Sonnar-type design and was consisted of 6 elements in 3 groups. The Sonnar-type design gave it great performance wide-open but the trade-off is you get more geometric distortion because of the asymmetric nature of this design. It is very well-made and it feels dense when you hold it thanks to the all-brass housing of this lens. The latter variants came in black and is said to be lighter because Nikon used some kind of aluminium alloy in place of the heavy chrome-plated brass.

IMG_3599If you guys are wondering where the focus ring is on this lens, then I will tell you that it doesn’t come with one! There’s no focusing unit for this lens because it uses the camera’s helical to do that. This has a trade-off, you get really small lenses compared to lenses for a camera that doesn’t have a in-body helical like the Leica system but the downside to it is you get a much more complicated camera with more things that can go wrong and the lens is somewhat limited when it comes to engineering and design because the engineer and designer will have to put this into account during the planning stage. To know more about how this works, check out this article on the Nikon S2 that I wrote.

Most earlier Nikon-made lenses and cameras were basically knock-offs of Zeiss products that were modified in some way to suit Nikon’s worldview and marketing purposes. This lens is a copy of the well-regarded 5cm Sonnar and they are more alike than different. It was difficult during the post-war years and Nikon doesn’t have much experience making consumer products so they have to start somewhere. This copycat culture changed when Nikon finally got the hang of it after a few years and they are now making better lenses than the companies they copied from and this was most apparent with the 5cm f/1.4 lens that came later. Known as the “Summilux killer” because it gave you similar performance for a fraction of the price. That lens was reissued in 2000 in limited quantities.

(click to enlarge)

The lens is very good wide-open but despite it’s C (coated) designation, the coating is not up to snuff compared to coatings made a few decades after in the 1960s. I imagine that’s great for it’s time and market positioning. The good thing is that Nikon’s coating is tough especially compared to what Leica was using and it is apparent from the samples that we see today. You will rarely find an old rangefinder Nikkor with serious cleaning marks. It was also said according to Jon M. that Nikon’s coating technology was developed from the experience gained making submarine periscopes and this is where the toughness came from. Images look great fro f/4 and and is awesome by f/8. I shoot with this lens most of the time so I know how this lens performs. Will it be able to go toe-to-toe with modern lenses? Probably not but it is still pretty good even for today’s standards. I will even say that this lens will give you a unique rendering when shot with a digital back and you can use that to your advantage! Get one if you are a mirrorless shooter! They are cheap.

(click to enlarge)

Here are more samples, this time shot with Ilford HP4+. It can be difficult showing what a lens can do when your samples were all shot with film so I am giving you the name of the film so you know what’s happening. Do bear in mind that Ilford HP4+ is known as a film with a higher than usual native contrast. Check out the first image with the sun in the frame, you can see that the Nikkor-H.C 5cm f/2’s old-tech coating can produce nasty ghosts in your image. Having that in mind, you should avoid strong lights in your frame to prevent this from happening. It really isn’t that bad, I’ve seen worse! The next couple of images of people were shot from around f/4 to f/8 if I recall. At this aperture, the lens is at it’s peak as you can see from the beautiful and crisp details on the people’s clothes. In the picture with the mannequins, the lady walking across the frame is kind of blurred. It might be because she was moving and also because I was focusing on the mannequins in the shop, this was shot at f/4 so there is some separation going on.

Alright! I think we can begin with the teardown now! Are you guys ready!?

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 (Main):

This lens is simple enough for most people to work on, provided he has the proper tools. I will admit that I didn’t get to open the rear optics cell since I do not have the right tool to open it. I will update this blog as soon as I fabricated one.

This lens doesn’t have a focusing unit as it uses the camera’s helical to focus in or out. I’m not going to separate the disassembly into several parts since this lens is simple enough to fit in just one section.

IMG_3600Begin by removing the front elements cell by using a rubber cup and unscrew it off from the rest of the lens. If you do not have a rubber cup, get a clean rubber glove and look for a tiny bottle that will fit the front. Now, cut a sheet of rubber material from the glove and make sure that it is bigger than what you need. Sandwich the rubber sheet between the base of the tiny bottle and the front ring and carefully unscrew it off.

IMG_3601When unscrewing the the front elements cell off, make sure that you do not damage the other end of it since there is a lens element there.

IMG_3602Now, let us go to the other end of the lens. You see the screw at the middle of the picture? Do not bother getting rid of it since it’s only there to keep what’s under it from rotating.

IMG_3603The rear baffle can be unscrewed off simply by using your fingers. If yours is glued, use a drop or two of solvent and place it on the seam and just let capillary action do the rest of the job for you. Wait awhile for the solvent to do it’s job and then give it another try. If it’s still stuck, repeat the solvent trick until it works. You will also want to try different types of solvents like alcohol or acetone. Industrial grade alcohol works best for me.

IMG_3604The rear baffle not only shields the lens from dust, dirt and stray light but it also secures the rear casing of the lens in place. Simply pull the casing from the rest of the lens and be careful NOT to damage the rear lens element. See the slot to the right of the picture? That is where the screw that I told you not to touch goes.

IMG_3605This brass shim is unique to each lens. It is used as a spacer of some kind to calibrate the focus of the lens so be sure not to lose or damage this part.

IMG_3606This mechanism is in charge of the aperture clicks. Its basically just an indented spring to click into the ridges on the aperture ring. Nothing fancy and it works! Some people don’t like aperture clicks and this is what you should remove in order to have a step-less iris.

IMG_3607To remove the aperture ring, carefully remove these (3) tiny set screws from the focusing ring. Be careful to take notes or mark it’s original orientation before you remove the ring to prevent you from wasting time later during reassembly guessing how this part mates.

IMG_3608Oh, here’s another one! You know what, I actually don’t recall how many set screws were there and assumed that there were 3. My apologies.

IMG_3609And here it is. Take note that I made a small mark on top of the indentation for the screw that can be found directly under the the f/2 mark. This will help me prevent any mistakes later during reassembly.

IMG_3610Next, time to remove the front ring. Simply remove this tiny set screw and be careful not to lose it. Notice that it has been sanded down at the factory. This part has to be flushed to the surface as to not impede the movement of the aperture ring.

IMG_3611The front ring can then be unscrewed off from the lens. Do the alcohol/solvent trick on it if your’s is stuck. Notice the depression on the threads. That is where your set screw goes! Be sure that you put it back together with this in mind, the set screw should sit in here.

IMG_3612The rear elements cell can only be removed using a special tool. The tool is basically just a short length of metal pipe and it should fit around the rear elements cell and it has two protruding prongs that sits squarely with the 2 slots that you see here. I do not have one at hand and I am too lazy to fabricate one so I just left this alone. I do not have anything much to clean here anyway! I will fabricate one in the future when I am in the mood.

IMG_3614The front elements call can be opened just like this. Since this lens is clean inside, I only had to blow anything there away. I do not know how the specs of dust got in here but I’m not going to leave it there.

That’s it for this part. It really isn’t difficult if all you want is to clean the inner surface of the lenses but it will require more effort if you need to go deeper.

Disassembly (Iris):

Only disassemble the iris assembly if you need to. It can take plenty of time to put it back together again. I am used to taking apart and putting back irises for non-automatic irises but this one took more time for some reason but I did it! Even lenses with even smaller irises didn’t take me much time to put back so I wonder what’s going on with this one.

This is a different specimen from what I’ve shown in the previous section. I had to open it up just to make the iris disassembly section of this article just for you to see! This is not going to be much helpful without this section so I had to do this!

The oil can come from the focusing collar inside which is usually lightly lubricated. Oil in an enclosed cell like this has nowhere to evaporate to so it precipitates o the lens and this is one of the causes of haze. Some grease leave nasty hazes that cannot even be removed.

IMG_4795Start by removing this retention ring. It simply unscrews off and you will need a spanner to loosen it first before you unscrew it with your fingers.

IMG_4796Next, unscrew this tall-headed screw. This screw serves as a pin to couple the iris’ cup to the focusing ring. Be careful not to damage this as this screw can be fragile at it’s neck!

IMG_4797Now, remove this collar from the objective’s casing. Do note this part’s orientation before you remove it, it is NOT symmetrical so you do not want to put it back in the wrong way.

IMG_4798Next, to remove this cup which also serves as a rotation plate you will need to use a pick to remove this brass ring. Be careful not to damage anything delicate at this point!

IMG_4799The brass ring can be difficult to remove if you do not have the proper tools. A sharp pair of tweezers will work but I use a pick with a sharp point for this.

IMG_4800The rotation cup can now be removed. I got it off just by using my fingertips to grasp the inner surface of this cup and pulling it up and away from everything. Be sure to note the orientation of this cup first before you remove it. The hole for the pin should correspond to the slot on the casing that is made for it.

IMG_4801OK, here is the iris. Do note how it looks before you separate it. Even experienced people in this repair industry with decades of experience can put an iris mechanism back in the wrong way. There are lenses where the direction of the blades are ambiguous and luckily for us this lens isn’t one of them! the W-Nikkor 3.5cm f/1.8 is such a lens.

IMG_4802Here are the individual leaves/blades. I wiped them all carefully with naphtha and some lint-free tissue. Be gentle with these so you will not warp them.

IMG_4803If you do not have the correct tool to remove the rear elements cell then this is a chance for you to clean the other side because the iris is now out of the way.

IMG_4804Putting the iris back together is very tedious and it requires several attempts sometimes. One quick way to distinguish which pin should go where is to look for the rounded end of the iris blade or iris leaf. The rounded end is connected to the base of the iris’ housing so it has enough space to clear for it’s rotation. Some lenses have iris blades that appear to be symmetrical so be careful with those! Simply lay out all of the iris blades until you cover most of the holes that can be easily covered.

IMG_4805The last few blades are the most difficult to put back. My favourite technique is to slowly and carefully slip a blade under the other one and then carefully push it into place using the pin on the other end. This takes practice to master but you will get used to it quick.

IMG_4806Here it is! After several tries and a lot of cuss words, it’s finally done! See how clean it is? Like what I said before, the cup should be put back in the correct orientation or else your iris will not open or close properly! As usual, always take plenty of notes.


I’ve been meaning to write this some time ago because I am still looking for a pipe with the correct diameter and thickness to fabricate a tool for the rear elements assembly but somebody needs a guide for this so I had to rush to write this article. Don’t worry, I shall update this as soon as I got this thing going. It’s just that I do not have an urgency for this until today. I hope this article will help my readers figure out how to overhaul/clean their Nikkor-H.C 5cm f/2 because many examples of this lens are in pretty bad shape due to the unfortunate status of being a “kit lens” of some sort. I even know people who simply use these as camera body caps for their Nikon S rangefinders! This doesn’t give justice to this little gem and I hope that more people will give it more respect after reading this article!

IMG_3613The lettering was faint and difficult to see on a sunny day so I have to repaint them using some enamel paints. Check out my lettering restoration blog post on how I do this.

IMG_4024So much cleaner now! In case you don’t have any lens caps and you have a pair of Nikon brand binoculars, the caps for the binoculars sits perfectly on the front ring! The ring is 40.5mm in diameter if I am not mistaken. Bring your lens to the camera shop and try the lens caps on sale there and see which one fits or you can order one online.

If you are bothered by the oily iris, you can clean it to a degree by using a Q-tip that was moistened with naphtha. This is the lazy way of doing things because the proper way is to open it up and cleaning every single iris leaf individually like what was shown here.

Thank you very much for your continuing patronage and support of my blog! If you guys enjoy my blog, please do not hesitate to share it because I have plans of monetizing this blog in the future. I just do not know how to do it and I am too busy to research on how to do that. If you have any information on how to monetize a WordPress blog then it is time that you teach that to me! See you again next time and keep on shining! 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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