I recently got a battered Russian MTO-500 f/8 lens,  a classic sample (or knockoff) of Soviet-era engineering and workmanship. It is a 500 mm telephoto mirror lens based on the design of a known Soviet engineer Maksutov. “MTO” stands here for “Maksutov’s Tele Objective”. Min looks like the the original, early MTO-500 design, with the...