Canon Control Ring Mount Adapter EF-EOS R lens mount_Adaptall This lens is an M42

This lens is an M42 mount

Regarding the rim coating loss: this is a common issue with older Schneider lenses

These fit over the narrow control knobs on early model Calypso and Nikonos lenses for a larger gripping surface

8 lens is for M42 mount cameras

so we've left it on

Canon Control Ring Mount Adapter EF-EOS R lens mount_Adaptall This lens is an M42The Canon Control Ring Mount Adapter EF EOS R lets you mount Canon EF and EF S lenses to EOS R mount cameras but it also adds a programmable Control Ring, like you'd find on native EOS R lenses. You can set it to do almost anything: control aperture, adjust ISO, destroy objects with your mind no you can not. But it's in excellent condition, with only very minor cosmetic wear.