It would be a mistake to assume only copying happened, Russian optics were good, leica factories acquired after the war but also strong physical sciences at university. Russians were perfectly capable of designing airborne folded optics.
My bad. Principle the same. Sad story: I am told Australia developed an optics industry in ww2 to supply the war effort. It was dismantled postwar for reasons i don't understand. Probably, was held to be innately unprofitable and not strategic. Similar investment in radar translated directly to csiro radio physics, the invention of one of the first computers, wifi, cutting edge science in lots of areas. Just not optics.
