Repair: Nikkor-H.C 5cm f/2 (LTM)

Hello, everybody! It’s still hay fever season here in Japan and it makes me wonder why it is not being addressed by the government. They could have replaced the trees with those annoying pollen with another evergreen that doesn’t do this. The cedar trees are the ones that are spewing the most pollen, I am sure that there are other varieties of evergreens that don’t spew allergens. Speaking of evergreens, I will now show you a different type of “evergreen”. It’s a lens that doesn’t seem to go irrelevant and it will continue to be useful for more decades to come. Read the article to know what this lens is.


Today, we are going to talk about the Nikkor-H.C 5cm f/2 lens in Leica thread mount! It’s the same lens as the Nikkor-H.C 5cm f/2 lens but it was adapted for use on cameras with the L39 (M39) lens mount. It has a 39mm thread that you can screw-in to your camera so it doesn’t come with a bayonet. For all intents and purposes, the optical performance of this lens is identical to its Nikon S-mount relative. Both were derivatives of the Sonnar, a venerable Zeiss lens design that offers good resistance to flare and is known to give nice and smooth bokeh. The Sonnar design is a protected under German law so Leica cannot make a copy or derivative of it. When Germany lost the war, the patents were made void outside Germany so other countries like Japan capitalized on this and made Sonnar-type lenses available in other mounts. It must be noted that Zeiss made a few Sonnars in the Leica mount but these are rare and expensive so the only way a Leica shooter can source one for cheap is to buy Russian or Japanese copies or adapt the Contax-mount ones to the mount of their choice. So, what’s unique with the Nikon version of this lens? Read on.

IMG_7501It’s a very compact lens but it feels dense because of the brass/chrome components used on the lens barrel. It’s also noticeably better-built compared to the other Zeiss-clones. The Nikon version feels more refined and the machining looks better than the Russian ones.

IMG_7545What’s peculiar about this lens is that this can focus very close. The minimum focusing distance for this lens is 3.5ft but you can turn the aperture ring past that and it can focus down to about 1.5ft! These distances are in red noting that the lens has decoupled from the rangefinder in the camera in “macro mode”. You mush use a special attachment on the camera for you to focus at these distances using the rangefinder.

DSC01144This is how close it can focus when set to 1.5ft, there is a click-stop on the lens that won’t allow you to focus any further unless you turn the lens further. This is a nice touch since it will prevent any accidental turning of the focusing ring past its coupled distances.

IMG_7597The Nikkor-H.C 5cm f/2 was frequently bundled with the Nicca 3s as a set because Nicca doesn’t have the capability to manufacture their own lenses back then. This make for a very nice walk-around setup. I enjoyed shooting with this setup a lot to be honest. This is the later black-ringed version and it fetches a small premium over the all-chrome earlier version. This is just a cosmetic difference and the optical formula remained the same as far as I know. Maybe it was tweaked a bit throughout its production life, who knows?

Canon also used Nikkor lenses way back in the pre-war years up until the post-war years when they don’t have their own lens making capabilities. This lens was usually sold with their cameras as a kit. They soon figured out how to make their own lenses.

As mentioned previously, this lens has the same optical formula as the Nikon-mount one. If you are curious about its optical performance, just check out this link for my pictures that were shot with film. Since film and digital behave differently, I will show you guys how this lens performs on digital here in this article.

DSC01145The lens renders exquisitely on digital. Look how delicate the picture looks, it is sharp in the areas where it’s in focus and then it gently transitions into out-of-focus smoothness. It is a characteristic of Sonnar-type lenses but some people don’t like this though.

DSC01154The bokeh balls look good but with some slight edging. Flare and ghost-resistance is good.  I shoot with the Nikkor-H.C 5cm f/2 a lot in both Nikon and Leica fit and I can tell you it’s not a bad performer when it comes to flare. The Sonnar was designed to have less air-to-glass surfaces to counter this in the age where most lenses weren’t coated. Use a pre-war Leica to get what I mean. As lens coating became commonly-used, this advantage of the Sonnar-type lenses becomes less and less exclusive. Sonnar-type lenses were not ideal for normal and shorter focal lengths for use on the SLR so it quickly went out of favor when it comes to shorter focal lengths as its design requires it to be close to the film plane but it remained popular for longer focal lengths.

(Click to enlarge)

The pictures above were shot from f/2, f/2.8 and f/4 respectively. Wide-open, you can see that the lens is already sharp where in-focus. Contrast is already good but stopping the lens down to f/2.8 will really make the center a lot sharper. By f/4, things improve even more and you can see that the resolution of the image improves. I believe that by f/5.6 it is beginning to peak in terms of resolution. Vignetting is obvious wide-open and it goes away by f/2.8, if that bothers you then you can alleviate it by over-exposing your picture a bit at f/2 to compensate for the darkening of the corners brought about by vignetting.

(Click to enlarge)

The set above should give you an idea of how this lens performs in real-world use. These were mostly shot wide-open. Just look at how smooth it is! It certainly has that desirable “classic-look” to it. It even renders some of the scenes in a very “painterly” way. Its bokeh looks nice and smooth, very typical of the Sonnar-type lenses but it can look bad at some situations where there is a lot of frequency in the background such as foliage and barks.

That’s it for the introduction. I wish to introduce you guys to Nikkors that were made in other lens mounts just to add some variety. We should appreciate all Nikkors whatever lens mount they came in and with that statement I’ll be making ones made for Bronica in the coming months. Let’s now begin with the repair article.

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 now-growing 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 (Lens Barrel):

The disassembly of the lens barrel is typical of early screw-mount Leica lenses. It’s easy to work on this lens if you’re a repairman familiar with older German or Russian lenses but it’s not something I will recommend a total beginner to work on. Amateur repairmen with the proper tools and some experience will find this easy. The lens can be separated into 2 separate assemblies, the front and the rear. The front assembly contains the glass and the iris assembly while the rear part is the focusing unit. The lens isn’t complicated to work on but there are some things that you should be careful with and I’ll show these later. As usual, take plenty of notes and measurements before you remove anything.

When working with chrome lenses, it is very important to use drivers that will fit the slot of the screws perfectly. If your driver doesn’t fit properly there’s a big chance that you’ll ruin the head or scar the screw’s surrounding metal. This is going to make your lens ugly and we want to avoid this as much as possible. I own several sets of drivers just for this but there are times when I need to modify a screwdriver by filing and sanding it so that it will perfectly fit a slot.

IMG_7503Typical of many older Nikkors, this lens has a retaining ring that you can remove so you can separate the lens into its basic parts. Use a lens spanner and position the tips on the holes and unscrew it. As you can see, somebody else has worked on this lens.

IMG_7504It should come off easily. Just like this. Don’t forget to place the lens on a flat surface with the bottom facing up or else the front assembly will drop to the floor.

IMG_7505The lens barrel/ focusing unit can now be lifted just like this. Be careful while extracting it so you won’t scratch the rear element.

IMG_7506This brass shim is used to calibrate the lens’ focus so don’t lose it. Put the front assembly in a safe place while you work with the rest of the lens.

IMG_7507Carefully remove the spring by unscrewing these 2. Be careful while removing it because there’s a small bearing ball underneath that can drop to the ground.

IMG_7508It’s a good thing that the bearing ball on my lens was caked with old grease so it stopped it from falling to the ground. Make sure that you don’t lose this thing as it is responsible for giving you the clicking-action when you extend the lens barrel to focus closer.

IMG_7509Make sure that the lens barrel is set to infinity always while you work on it. This will be useful because you will have a point of reference later when you reassemble your lens. I always take my notes while the lens barrel is at infinity for this very reason.

To remove the focusing ring, extract these 3 screws. Make sure that you use a driver that is a perfect fit to the screws’ slots to prevent damaging it or scarring the metal around it.

IMG_7510The focusing ring can now be removed. Notice that I made a small scratch to help me in identifying which dimple should be closest to the lens barrel’s midline.

IMG_7511The brass helicoid has a fine thread and that can be tricky to put back correctly at times so I took as many notes as I can. I first collapsed the helicoids as far as I can and I made a small mark to remind me how far it went. When I put the lens back I should get the same result or else I got everything wrong and I will have to start all over again.

IMG_7512One more important thing to do is to take note how far out this channel is. You can use a caliper to measure the distance or just take note of the position of the grooves. Scratching this part is not a good idea because something else moves within the channel.

IMG_7513Here’s a picture of the inner surface of the lens barrel. Just take as many pictures as you can before disassembly, you only have one chance to do this.

IMG_7514The inner helicoid can now be separated. Note that the previous guy who worked on this lens made a mark to note where these should mate.

IMG_7515The central helicoid can now be separated. Again, the guy who worked on this made this mark. This will come in handy later.

IMG_7516The infinity lock can be disassembled by removing this screw.

IMG_7517The button can now be removed but be careful not to lose anything under it.

IMG_7518The busing comes off next.

IMG_7519Make sure that you don’t lose this tiny spring.

That’s it for the lens barrel. Be careful with the helicoids and mark where they separate. I will not be held responsible if you messed this up and end up with a box of spare parts. If you messed this part up then guessing how the helicoids should line-up is not going to be easy because the central helicoid has a fine thread. There are also many small parts here and it feels more like working with a small clock than a lens.

Use a thin type grease for the helicoids and don’t apply too much because the excess will find its way to the iris. Applying a thicker type of grease will just make this lens difficult to turn and focus. There is also the danger of it unscrewing from the mount if you turn it too much.

Disassembly (Objective):

The front assembly is the most complicated thing in this lens. You will have to be careful with the glass because Sonnar-type lenses have lots of cemented surfaces. Solvent can be accidentally applied to the cemented lenses and that can ruin the cement on the lens. Use the proper tool and don’t apply too much solvents and you should be fine.

IMG_7502The front ring can be unscrewed just like this.

IMG_7521The front bezel (name ring) can be removed with a rubber cup. There are 2 small holes here so you can use a lens spanner but I used a rubber cup because it’s soft so it will not leave any marks on the surface of the bezel. There is oil on the iris and we need to clean this as soon as possible!

IMG_7522The front optical cell is attached to the bezel so it comes off along with it. Make sure that you don’t scratch the glass at both ends of the front optical cell.

IMG_7525The front optical cell can be opened by carefully unscrewing this retainer ring. Carefully use a lens spanner to open this. If it’s sealed, use some alcohol and saturate the threads to soften the lacquer. Make sure that you don’t put too much alcohol because the 2nd and 3rd elements are cemented. Alcohol will damage the bond and result in glue separation. I will have to warn you about opening this because you may scratch the glass and it’s also an old lens so you may accidentally separate the bond of the 2nd and 3rd elements.

IMG_7526The retention ring can be removed just like this. Only use the lens spanner to loosen the ring or tighten it then use your fingers to do the rest of the job.

IMG_7527The cemented triplet can now be removed with a lens sucker. It’s called a triplet because it’s composed of 3 separate lens elements that were cemented together into a single unit.

IMG_7528The bezel actually consists of 2 separate parts. Use a rubber cup to separate the bezel so you can remove the front element. To be honest, you don’t need to do this if all you need to do is clean the surface of the front element because you can access them anyway.

IMG_7529If the name ring is stuck, just do that alcohol trick to soften the glue. Mine came off easily and it wasn’t glued at all.

IMG_7530The front element can now be easily extracted.

IMG_7523The rear element can be removed by using a special tool called a “pipe key”. If you don’t have one, you can make an alternative tool just like what I have here. If you haven’t seen it, read my article on how I made this tool by clicking on this link.

IMG_7524The rear optical cell can now be safely extracted. Remember, loosen the rear optical cell and use a lens sucker or your fingers to unscrew it off so you won’t scratch anything.

The glass is easy to clean because Sonnars have few air-to-glass surfaces. When cleaning the glass, make sure that you don’t get solvent into the cemented elements. If your lens is riddled with fungus, don’t soak the cemented elements in a bath. Saturate a Q-tip or lens tissue with your solution of choice and carefully wipe the fungus away. You should treat cemented lens groups with utmost care.

Disassembly (Iris Mechanism):

The iris mechanism is a bit more complicated with this lens since there are more parts in the assembly involved but it’s a lot easier to work on this than working on Zeiss lenses. It has a few adjustment points that you will have to be careful with and there are parts that are very small here that can be lost easily. Remember not to oil the iris or anything close to it except for the aperture ring’s thread. A very thin film of grease is all you need. If you put plenty of grease here then it will migrate easily into the iris.

IMG_7532Before you can get to the iris, you must first remove the aperture ring. To remove it, you must first remove the click-stop mechanism by removing these 2 screws. The spring can be adjusted so take note of its position first before you remove it.

IMG_7543There is a small bearing ball here that you won’t want to lose. It was stuck due to grease so it stayed there. Clean this properly if you can.

IMG_7533The aperture ring is secured by this ring. The ring is then secured by this small screw. It’s a small set screw so make sure that you don’t lose it.

IMG_7534Once the set screw is gone you can now unscrew this ring off. When putting this back it’s important to put it back properly or else the aperture ring will sit too high or too low. It’s also important that the set screw should be screwed properly to its hole.

IMG_7535The aperture ring can now be removed.

IMG_7531The iris mechanism is being secured by a brass ring. Carefully pry this brass ring off so it can be opened and make sure that you don’t damage anything here. I use a small dental pick with a sharp point to pick at the brass ring.

IMG_7536As you can see, there’s some grease here for the aperture ring. Make sure that you don’t put a lot of grease here to prevent the lubricant from migrating to your iris. The screw in this picture has to be removed because it’s in the way. It couples the aperture ring to the iris’ cup inside the iris assembly’s housing.

IMG_7537The rotator cup can now be removed. Before removing it, make sure to note its position when the iris is wide-open. You will have to put it back the same way.

IMG_7538The iris is all gummed-up with oil. Make sure to take note which end of the blade should go where. The ends aren’t symmetrical and if you put it back the wrong way the iris will not close-down properly. There’s also the possibility that you’ll permanently damage it.

IMG_7539The iris was so oily that it came-off like this.

IMG_7541Each individual iris leaf was cleaned properly using benzene. They can rust and if yours are rusty just soak it in benzene with a drop of oil. Leave that overnight and wipe the oil and benzene away with a soft lens tissue. be careful not to damage the iris leaves, if you bent or warped one then your iris won’t operate smoothly.

IMG_7544The iris was rebuilt carefully. All the oil is now gone and it’s now very clean! Rangefinder camera lenses have irises with interleaving iris blades and they are more difficult to put back than usual automatic iris lenses because they have more blades and they intersect. If you’re having trouble with this then read my guide on how to repair a preset-type iris.

The iris is now dry and clean! You never ever want to oil anything here. As we previously discussed, we only want a thin film of thick grease on the aperture ring’s thread. That is the only place that requires lubrication in this assembly.


The lens was given a very thorough cleaning and it’s now very clean. I got the lens from a junk auction and the inner elements had what looked like tendrils. I was OK with that so I bought it thinking that I can clean that. I cleaned the inner elements and I was relieved to find out that the tendrils aren’t fungus damage but just some dirt from the iris. It was cleaned thoroughly and now everything looks very good. I just got rid of decades’ worth of dirt from this lens and it’s now worth more than the price that I got it for,

IMG_7540The engravings on the lens were all re-painted. They were worn so this had to be done. If you don’t know how to do this then read my article on lettering restoration.

IMG_7547The lens is now clean inside-and-out! It’s no longer a junk lens!

IMG_7584See how shiny it is now? It looks gorgeous and it certainly feels very luxurious to hold in your hands. This lens will certainly out-live me and exceed 100 years of use from now. It just had a nice overhaul and if this lens could talk, it would say “thank you”. This lens is a true classic and is always relevant as many Leica photographers’ first cheap 50mm lens. I dare say that the demand for this thing doesn’t really go down as much because of that. It is now rising in popularity because it is easily adapted for use with mirrorless cameras.

I had so much fun working with this lens. It had the right amount of complexity to keep me entertained for the evening. I probably spent some 3-4 hours working on this thing. I spent most of the time cleaning and repainting the engravings. The lens was really dirty when I got it that cleaning and polishing it just a bit brought out the shine in the chrome back again. The lens now looks stunning and is certainly a head-turner when I use it on my Nicca 3s. This is the only Leica thread-mount lens that I have at the moment and I am going to buy more in the coming months so I can use them with my Nicca 3s.

I hope that you enjoyed this article. I am still sick with hay fever so it took several nights for me to write this. I wanted to show introduce you to more Nikkors that were not made in Nikon’s native S-mount and F-mount. I am hoping that I can generate interest in these old gems and I want to show people some really good and cheap alternatives to the over-the-top priced Leica lenses. See you guys next time and I hope that I will feel better next week so I can have the energy to write another article. Thanks for understanding, 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.

Buy me a roll of film or a burger?

Thank you very much for your continued support!


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.


1 Comment (+add yours?)

  1. Trackback: Repair: Nikkor-H.C 5cm f/2 RF | Richard Haw's Nikon Maintenance Site

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