Mamiya 7 80mm Lens: Unsharp Images, Cam and Focus Calibration
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
My client sent in his Mamiya 7 and 80mm lens complaining of images that did not have optimum sharpness.
On checking the camera rangefinder, I found it to be out of spec slightly. Also, the lens, as seen in the first photo, was also out of rangefinder spec by a little (-0.035mm). Both of these situations could cause a small loss of image quality if you were shooting wide open at closer distances. But this was not the case as I was told that even infinity images were not sharp. Checking the lens closer on the auto collimator, the second photo shows an image that is not quite sharp. Stopped down you might not notice the loss of quality but lenses are tested wide open.
In most cases, when I find Mamiya 7 lenses that are not in spec on the rangefinder cam and/or focus, the lens shows signs of previous service. Without the correct factory tools, these lenses can be challenging to properly calibrate.
After service, photo three shows the lens rangefinder cam right at zero and the image in the collimator in the final photo is very sharp.
