>>3242423fun fact: for the pictured industar-50, the russians just added an extension tube and focus registration tube to the lens, if you unscrew the rear of a rangefinder m39 industar-50 you get an SLR m39 pankek that, through a m39>m43 converter ring and removing the focusing limiter pins can be plopped on any DSLR or mirrorless with an m42 adapter. Free pancakes from cheap/abundant rf m39 shitprimes for all!