1, Ricoh double reflex is a Rikenon lens with 80mm antenna insertion structure, which was produced by Ricoh Corporation of Japan in 1957. The design of the focusing system is the most special part of this double-reverse, and the ingenious concept facilitates quick shooting.

2. Seagull dual-mirror camera is copied by Shanghai Camera Factory on the basis of German Lorai dual-mirror camera. His unique appearance and convenient photography process left a strong impression on him in the history of traditional photography.