Jupiter 8 Repair Question - Focus Issues

[mcgarryr]

First off I'd like to thank all of the participants in this forum. The wealth of information posted here has been a tremendous help while purchasing and fixing up my first FSU rangefinder.

My question is this. I recently purchased a Zorki 4 with a Jupiter 8 lens . I shot a quick test roll with a variety of aperture settings and of scenes and objects near and far. Unfortunately anything beyond 1 m away or so appears terribly blurry. So I took the lens apart while consulting Kim Coxon's Jupiter 8 Service Guide. Everything seems in order except there is only one alloy shim instead of the 2 pictured! Mine is the "Lens 4" style.

Is this the most likely source of my problem? Can I make a new one myself, perhaps out of wire? If so, does anyone know off-hand the thickness of these shims?

Thanks in advance for any help, and for all of the helpful material that's been posted here already!

 

[Ed S.]

The Kiev Survival Site might have the answer you need.

Specifically, this page might be able to help you determine the cause of your problem.

 

[Spyderman]

The pictured shims do not mean you need 2 !

the shims were added at factory to calibrate each individual lens.

There are more factors than just the shims:
- body register distance = film to lens mount flange distance = 28.8mm (measure with vernier caliper ! )
- lens mechanical assembly (multi entry-point threads ? )
- body RF calibration (infinity AND CLOSE RANGE are adjusted separately ! )
- lens working distance = thickness of shims (they move the lens farther / closer to film) You can make them of various types of paper, coke can...)

You should check all these in the order as I wrote them.

 

[mcgarryr]

Thank you both very much! Looks like I have my work cut out for me but at least I now know where to get started. The film to flange distance seems about .5 mm short so I'll start there.

 

[mcgarryr]

Well it seems I was way off. Testing with a ground glass revealed that the one shim that was in there was too thick as it was. I made a few paper ones to replace it and the results are dramatically better. A little more fine tuning and it should be as close to perfect as could be reasonably expected.

I'm really new at all this, even just photography in general. Thanks very much for steering me in the right direction and saving me the embarrassment of having a $40 paperweight. 🙂

 

[mcgarryr]

Thank you very much for your warm welcome. And I will certainly look out for that. Hopefully I'll have post-worthy pictures to share in the not too distant future.