Mamiya Press 50mm f/6.3: Stiff Focus Helical Cleaning
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This 50mm f/6.3 (Biogon type) is the widest lens made for the Mamiya Press cameras. This example came into the shop with a very common issue of stuck/tight focus. Solution is removal of the focus helicals and cleaning them of old grease.
One reason why these lenses get stiff focus quite often is that they have a large focus helix and there is only one focus guide as seen in photo three. These lenses have a standard Seikosha S shutter buried in the lens barrels. This is what makes service on these lenses a little more time consuming as the control levers of the shutter (cocking lever, sync lever and diaphragm control) all have to align when putting the shutter back into the barrel.
Also, Mamiya seemed to have gone very heavy on thread sealer with these lenses. Photo four shows how the one focus guide was attached to the barrel with a sealer and needed heat to release.
Final trip for the lens is to get checked and adjusted for focus.
