RB67 37mm Fish Eye: Replacing a Butchered Locking Ring
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This Mamiya RB67 37mm Fish Eye lens gets my vote for “Most Butchered Repair of the Week”.
My client purchased this lens knowing that the locking ring had some damage but was told that it was cosmetic in nature. Not really true. The ring had suffered an impact and an attempt was made to fix this at some point by grinding, filing and cutting. You can see the slice made from a cutting wheel and it even extends through to the center plate and to the threads. And, after all this, the lens will still not mount on a body.
These locking rings are often impact damaged and they are very difficult to straighten out because of the curves. Even if it could be straightened out good enough to mount on a body, it will still have evidence of the trauma in most cases.
The last photo shows the only real solution: replacement of the locking ring (and in this case, the center plate since it was damaged in the “repair”)
