Russian M39 lens mount adapter help?

Aaralli · November 20, 2022

Hello. I recently bought an old "MTO-1000" 1000mm lens, built in Soviet era Russia. It is the oldest version of the lens as well, making it much heavier and harder to work with than the ones from the 80s. It has an M39 mount, but when adapting to Canon's EF mount and then using it on an EOS R7 with an EF-RF mount adapter, I couldn't quite reach infinity focus. It seems I was off by a HAIR, like a millimeter or less closer to the camera body and I would've been perfect. Does anyone know an adapter for the Russian version of M39 mount to RF directly? By the way, I cannot adapter this lens to a Canon DSLR as far as I can tell, because the flange distance requires that the edges of the lens would be INSIDE the grip and built in flash. I've attached some images of the MTO-1000 lens for reference and explanation as to why I need to use a mirror less camera.

Eviljuche · March 25, 2023

Hi! This is an old thread, but I hope you'll get notified about my response.

Soviet M39 is not compatible with a regular Leica's M39 because of the 2 key factors - slightly different mount grooves and a completely different rangefinder control lever. Some adapters might do the trick, but the results might be kinda off as well, usually with infinity focus being impossible.