Mamiya 7 43mm Lens: Checking the Rangefinder Cam
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
I was recently asked about my process for evaluating lenses for the Mamiya 7. In addition to other inspections, every lens has an initial check up of the rangefinder cam as shown in these videos. First video shows the rangefinder cam calibration standard installed on the test fixture to insure that the dial is set to zero. The second video shows a 43mm lens installed for checking and in this case, it was off by (-0.015). Not a huge deal but still out of specs and would be adjusted. Specs are (0.00 to 0.015).
Whenever the lens is disassembled, this measurement needs to be taken and adjustments made if necessary. In this case, the lens came into the shop out of specs. The third photo shows the adjustment screw and you can see that it is a little chewed up (not bad compared to others I have seen) and this is typical of what I encounter, especially when a lens comes into the shop out of calibration as Mamiya puts these screws in with a very strong sealer (maybe evidence that the lens has had a prior adjustment done/attempted?) .
