RB67: Removing a Stuck Lens from the Body
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
I’m making this post as a further clarification for the YouTube video that we did some time ago on getting off a Mamiya RB67 lens that is stuck on a body.
I get a lot of requests from people that have a stuck lens on the RB67 and they can’t get it off using the technique that I show on the YouTube video. The key as to if the technique will work is that the locking ring is still moveable, just not able to fully reach the top index mark on the body. What happens is that for various reasons, the body will not fuly cock. This could be a lens or body issue and since the lens will not come off unless the body is fully charged, the lens is stuck. And, the first thing we want to do is remove the lens to evaluate where the issue is located.
If the lens lock ring will not move, then you either have a damaged ring from an impact or from it being put on too tight. Photo one shows the correct tightness of the ring, the red dot should be at around 60 degrees (about at 2 o’clock) from the top red dot index ring. Cranking the lock ring really tight will cause an issue, especially if the ring has some dirt or debris in the threads.
The second photo/video shows the rangef of motion on the ring when the body has been released and the lens ring is hitting the blocking lever. The third photo/video shows what is happening when you probe the emergency lens lock release with a pick (lens removed to show how the blocking lever is moved). My YouTube video shows a bit more detail on the operation.
If the lens lock ring has even a small bump or impact, it may not want to move and more drastic measures are called for, such as very, very careful use of a strap wrench.
