Dan, the only way to mount Rodagon-G 210 M72 lens on Copal #3 seems to be screwing it to the shutter's front thread, which is recessed about 6 mm. I do have a high-quality M58-M72 0.75 step-up adapter with threads longer than those usually found on Chinese adapters. But it's outer diameter is larger than the front opening of #3 shutter and I'd need an approx. 10 mm M58 extension ring of comparable quality and thread length. The only such ring I know of is a really expensive Schneider extension tube for Unifoc system, and I don't know if the threads are long enough to have everything tight. Or did you perhaps have a totally different idea for mounting a M72 lens in front of a Copal #3?
Originally Posted by Dan Fromm