The Russian MTO-500 is a classic sample of the 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 for “Maksutov Tele Ob’ektiv”. This is the original, early MTO-500 design, with the barrel made of brass. Later versions of this lens were much lighter and somewhat smaller, they came is vinyl cases, but this MTO-500 weighs 1.5 kg (3.3 lbs) and comes in an instrument-type wooden case.