Zorki ZK 1:2 F=5cm Contax/Kiev disassembly?

[Kai-san]

I've got a hazy Zorki ZK 1:2 F=5cm in Contax/Kiev mount that I would like to clean up if possible. I have not found any help online, maybe someone here has worked on this lens? If so I'd be happy to get some tips.

 

[dexdog]

This link to the archived Kiev Survival site has some info and pictures. The ZK in Kiev mount should be very similar to the lens worked on at the site provided that your lens is rigid version, and not the collapsible version

Kiev Survival Site

Jupiter-8 Lens Dismantle and Clean

web.archive.org

 

[Kai-san]

I have the collapsible version, but if the lens is otherwise similar I think it might work. The collapsible part is basically a ring with a locking mechanism, and I can access the set screw on the mount base. I'll give it a try. Thank you!

 

[Sonnar Brian]

The 5cm F2 is identical to the Carl Zeiss Jena 5cm F2 collapsible Sonnar.

The Barrel is held into the mount with a small set screw, visible with the lens in the collapsed position.

 

[Sonnar Brian]

The Small Screw closest to the mount holds the barrel into the mount. Once the set screw is out, the barrel unscrews. It might be very tight. Be careful of the Shims- which can be as thin as 0.01mm metal.

 

[Kai-san]

Thanks for posting the disassembly shots, Brian!

 

[Sonnar Brian]

Thanks for posting the disassembly shots, Brian!

You are very welcome!

For anyone else looking for disassembly instructions for the ZK and Zeiss 5cm F2 Sonnars, pre-war and wartime:

CZJ Sonnar 5cm F2 disassembly: Rigid Mount with Filter Ring, Collapsible Mount

A relatively uncommon version of the 5cm F2 pre-war Sonnar that has an "adapter" to fit into the rigid mount of the 5cm F1.5 lens. Held in by one set screw, same as the F1.5 lens. And the more common collapsible lens, also held in by one set screw- but in a different location.

www.rangefinderforum.com

 

[Kai-san]

The instructions and photos were very helpful, and I managed to take the lens apart, clean it and put it correctly together. But it was as I feared, the front glass of this lens is damaged by repeated cleaning over the years.

 

[Sonnar Brian]

The 5cm F2 Sonnar is low contrast used without a filter, and has softening due to chromatic aberration.
Try a Yellow-3 (y52) or Orange ( O-56) filter on it.

This is with a clean 1934 5cm F2 Sonnar, Orange filter.

 

[Kai-san]

The photo below is shot with a ZK 2.0/5cm in LTM mount. I don't really think a filter will bring this lens to the same level, so unless I can get hold of a new front glass it will be relegated to the "special effects" section.

 

[Muggins]

Hmm, dare I try to clean this as and when it returns from having the shutter fixed? It's hazy with an oily aperture.

 

[TenEleven]

Hmm, dare I try to clean this as and when it returns from having the shutter fixed? It's hazy with an oily aperture.

Check the front lens, if the front lens is in good condition (no dense so-called "cleaning marks") these uncoated Sonnars are quite fixable usually. The glass on these rarely goes bad and the haze from the off-gassing of the oil can be usually cleaned.

Also make sure that the set screws (collapse the mount up towards the lens, there should be two screws) are not mutilated. I had a copy where someone mutilated the set screw meaning I had to drill it out. I got a very fair price because of that but something to be aware of.

 

[Sonnar Brian]

Replacing the front element is difficult as the glass is in a brass fixture. One RFF member (@TenEleven , was that you?) replaced the front element, required breaking the glass and mounting the new element.

 

[TenEleven]

Replacing the front element is difficult as the glass is in a brass fixture. One RFF member (@TenEleven , was that you?) replaced the front element, required breaking the glass and mounting the new element.

Yes that was me. And to be honest I did not intend to break the glass.
I left it in strong solvent (paint thinner) for a while heated it as hot as I could bear and pushed on it.. it felt like it was going to go but then instead cracked. Miraculously the same stupid "trick" worked for the donor, so I could proceed. Would i do that again now that I am wiser? ... probably no.

By the way, the rigid ZK's f2 have a loose front element that is held in by the name plate. You could potentially substitute a post-war jena 3mil+ f2 Sonnar front glass. However I think the computation might be slightly different. The diameters are slightly different too but there is enough play that it will work, just not sure what the optical performance would be like.

 

[Kai-san]

Replacing the front element is difficult as the glass is in a brass fixture. One RFF member (@TenEleven , was that you?) replaced the front element, required breaking the glass and mounting the new element.

The collapsible ZK 2/5cm has a loose front glass too like TenEleven described. Easy to replace but difficult to get hold of.

 

[Sonnar Brian]

The early J-8 should be a good donor for front glass. I have 3 from 1952, meaning German glass. I have one with Zeiss cut glass in it.
I ordered a digital Radius Gauge- between that, and digital calipers, should be able to compare the two.
I recently picked up a 1948 5cm F2 ZK, and a 1950 5cm F2 ZK. Both collapsible.

 

[Muggins]

Check the front lens, if the front lens is in good condition (no dense so-called "cleaning marks") these uncoated Sonnars are quite fixable usually. The glass on these rarely goes bad and the haze from the off-gassing of the oil can be usually cleaned.

Also make sure that the set screws (collapse the mount up towards the lens, there should be two screws) are not mutilated. I had a copy where someone mutilated the set screw meaning I had to drill it out. I got a very fair price because of that but something to be aware of.

Thank you for the tips, much appreciated!