Zorki S with Fed 50 lens - lens doesn't appear to be engaging rangefinder cam?

[BHuij]

Hey everyone--

I just got a Zorki S, my first 35mm rangefinder. The first thing I noticed was that it was incredibly dirty haha. The second thing I noticed was that the rangefinder images didn't move at all when I moved the very sticky focusing lever.

I took the lens off and CLA'd it - cleaned elements front and back with microfiber, scrubbed all threads out with alcohol and cotton swabs, and carefully re-lubricated with some PTFE lube. Got the aperture adjustment working much more easily and smoothly, focusing is much better, etc. etc.

While the lens is off, there's a cam arm clearly visible on the camera body. It moves easily and smoothly, and the return spring has no trouble pushing it back into the forward position. What's more, the rangefinder appears to be working perfectly. The images converge and diverge exactly as I would expect when I just move the cam by hand with no lens attached.

Sometimes immediately after attaching the lens in the infinity position, I can get a little movement in the rangefinder with the focus lever as a slowly bring the focus closer. Seems like once I pass a certain point though, it will no longer push the cam back as I reverse back towards infinity, and at that point the cam is no longer moving when I adjust the lever in either direction.

So as near as I can tell, the inner lens barrel that moves in and out with focusing is just not engaging the arm of the rangefinder. Couldn't tell you why. The frustrating part is that I can't just remove the back to see what's going on inside while the lens is attached, because it's a bottom-loading camera. But the focus tends to stiffen up as I get close to infinity, despite being freshly lubricated and feeling buttery smooth when the lens is off the camera. It feels like the lens barrel is just scraping the bottom of the rangefinder cam rather than pushing it back.

Near as I can tell the rear part of the lens is normal and within spec. The front is a little banged up, but that shouldn't have any effect on this. Does the Fed 50 just not work properly with the Zorki S?

Pics here, I can take more if someone needs to see something specific to help me troubleshoot:

https://imgur.com/gallery/4YsBa0O

 

[E. von Hoegh]

The follower (lever on the camera) is not aligned with the cam (ring on the lens)and is slipping off to the side of the cam (stiff focussing).

 

[Ko.Fe.]

Fed-50 is regular industar-10. It works on any rf camera.
Google Jay Fedka. It shows how to remove body with top plate and shutter still connected.
Or do some marking on rf cam on the lens. Same trick like they do with in dentist office to see the contact.

 

[E. von Hoegh]

Fed-50 is regular industar-10. It works on any rf camera.
Google Jay Fedka. It shows how to remove body with top plate and shutter still connected.
Or do some marking on rf cam on the lens. Same trick like they do with in dentist office to see the contact.

Your first suggestion is impossible, there will be no way to mount the lens.
Second is supurfluous, the issue is obvious & can be resolved with a 6" machinist's scale and a bit of care.

 

[BHuij]

Never did get the Fed-50 working. I did obtain an Industar-50 and tried it on today. Works perfectly. When I put the internal cylinder of each lens up against each other, the Industar-50 is quite noticeably larger in diameter. No idea what the deal is with that Fed-50, but now I have a working lens I'm not too worried about it. Excited to see what comes out of the first roll.

 

[Vaidotas]

In my experience FED50 is the worst choice from all soviet m39 rangefinder lens. They were produced in different modifications and I suspect this one just dont fit your camera.

 

[Ko.Fe.]

In my experience FED50 is the worst choice from all soviet m39 rangefinder lens. They were produced in different modifications and I suspect this one just dont fit your camera.

All of Collapsible Industars were produced in different modifications. FED-50, if not coated, might be from prewar batch, during this time each camera, lens were made as individual pair.
FED-50, aka I-10 is the only lens from this series which is matching the Elmar one by one in size and build.
After it, they made them bigger and different.

 

[McFortner]

The cam is probably too high up and is catching on the back of the screw mount of the lens. I had a couple of FSU rangefinders that did that.