I'll check my books, but I think the problem is likely that you have the wrong lens. The 37 mm Mir with 39mm lens mount was intended for use on the early SLR Zenit cameras so the back focus is probably wrong for your R2.Originally Posted by Elmer Fishpaw
It may be possible to adjust the 37mm MIR to focus on your R2 - it's worth asking a camera repair person. I would just buy a 2.8/35mm Jupiter 12, which is a Zeiss Biogon design and an excellent performer. It was an RF lens from the start (FED/Zorki/Leica 39mm screw thread and Kiev/Contax bayonet versions are available).
I use 2 Russian WA lenses on my Minolta CLE and my Leica M3s. They are the 4.5/20mm Russar and the 2.8/35mm Jupiter both are 39mm thread RF lenses that were built for Russian/Ukrainian RF cameras.