Originally posted by monochrome Interesting and timely. I have an SV with serial number 969033 but also with an orange R on the dial. I have an 8-element ST50/1.4 in transit, a nice 7-element and several low serial ST55/1.8's (as well as a number of later normals - older friends just drop their gear off on my doorstep from time to time). I had hoped to use the 1/4's on the SV but I suppose they'll have to stay on the later M42 bodies.
How did you test for the mirror collision?
Carefully!
First, I covered the back lens with a round piece of easy-to-remove tape. I set the camera body to B and opened the shutter/flipped up the mirror, then I screwed in the lens, set to infinity, and "un-released" the shutter. This was enough to prove that the mirror was hanging instead of freely moving back. I don't remember how I proceeded from there, but now I think in order to avoid touching the mirror with the pin or somehow exerting pressure on it, it would be best to open the shutter again before removing the lens.