Why probably? Well, it came attached to an obviously fake Leica. So, the one thing I’m pretty sure of is that it’s almost certainly not a Leitz (i.e. Leica) Elmar as it says on the front plate. After a bit of research, I think it’s probably an Industar 22. This lens was produced for a number of 35 mm cameras made by KMZ in the Soviet Union from 1948 into the 1950s. I can’t say exactly when it was made as that would require looking at the serial number, which has conveniently, and not surprisingly, disappeared from this one. It is a 5 cm f/3.5 Tessar-formula lens. It was first made as a collapsible lens in Leica 39 mm screw-mount, for the Fed and Zorki rangefinders. It resembles Leica's collapsible 5cm f/3.5 Elmar. Apparently about 20,000 were made.
