Rangefinder adjustment

[NikonSP]

Am I supposed to readjust the rangefinder on my IIIc everytime I want to use a different 50mm lens. My IIIc original came with a 50mm f/1.5 Sonnar (transition lens made from wartime parts). I really wanted a collapsible lens so I settled on a 50mm f/2 Summitar. I have the rangefinder adjusted for Summitar. When I put the Sonnar back on the rangefiinder shows infinity but the distance scale does not. It is atound 7m. What is going on here?

 

[Mr_Flibble]

No, there shouldn't be a need to adjust the RF at all. I think maybe one of your lenses needs to be adjusted, not the camera.

 

[John Shriver]

Take both lenses off the camera. Set both to infinity. Measure how far back from the flat plane of the lens mount the rangefinder cam is. It should be exactly 7.5mm. If it isn't, that lens is assembled wrong. Both have multi-start helicals, so either one could be assembled on the wrong start.