FSU Rangefinder path adjustment

[Daimon]

Question about rangefinder adjustement. But not a standard RF rotating window + adjustement screw.

I noticed that some FSU rangefinders tend to have a crooked rangefinder ghost image. Did some checking and culprit is clear - RF mirror is not aligned with beam splitter plane.

Any guidance on how to perform adjustement process?

Example from my Zorki 6 on how bad it can be 🙁 (yes, it's not possible to calibrate RF at all on this camera using a standard method)

 

[dxq.canada]

Is there a big screw with a washer on the back of this prism?
If so I am guessing that is this securing it ... so you should be able to loosen it and adjust the tilt.

 

[Daimon]

Yep it's there. But I'm more wondering about proper "process".

- main prism with beam splitter may have some tilt and it's not adjustable
- RF window prism has adjustable axis - by loosening 2 screws marked by red arrows it's possible to slightly skew axis itself
- then as you mentioned it's also possible to rotate prism itself by loosening screw on back (blue arrow)

 

[dxq.canada]

I would guess the two top screws would give minor adjustment ... and the screw in the back for major movement (which it appears your prism needs).

 

[Daimon]

Ok so to make it clear there are 5 screws there but one is in the shadow 🙂
- 2 big marked by red arrows - those allow to move top plate effectively changing axis (i.e. changing ball bearing position)
- 1 big on the back of prism - marked by blue arrow - this should loosen prism itself
- 2 small these allow to fine tune prism axis (which is orthogonal to the axis controlled by red arrow screws)

 

[dxq.canada]

Hmm, I cannot provide any experienced advise as I have never worked on a Zorki ... just guessing based on the images I have seen.