Mamiya 7 65mm Lens: Recalibrating the Rangefinder Unit
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This Mamiya 7 65mm lens needed some servicing to the shutter mechanism that required the shutter to be removed from the lens. This means removing the elements, flex cable, rangefinder assembly and then the shutter.
When the rangefinder unit is removed from the lens, it needs to be checked for calibration when re-installed. In this case, before disassembly, the rangefinder unit checked within specs at (-0.015mm). As you can see in photo three, after re-assembly the rangefinder is at (-0.04mm). This would cause the rangefinder image in the camera to not quite meet at infinity. So, it needs a bit of adjusting. Unfortunately, Mamiya put the adjusting screw in with a sealer and used a fairly fine slotted head adjusting screw. I often see these screws damaged and in this case that was true. To loosen the sealer, Mamiya recommends using a “cigarette lighter”. I prefer to use a hot air reflow system set at 900 degrees with a small tip focused on the adjusting screw and housing as seen in the final photo. It is a bit of a pain.
