The FAN-1 is a wide-angle converter manufactured by ART-Filmotechnik in Minsk, Belarus. It fits on the front of the standard lens using the filter thread, and comes with adapter rings to fit M52, M58 and M62. According to the instruction leaflet, M55, M67 and Rolleiflex bayonet adapters are also available. Fitting this adapter to say a Volna-3 80 mm lens converts it to 50 mm, and fitting it to a Helios-44 50 mm lens, converts it to 31mm (i.e. a factor of 0.63). It can also be used on projectors and enlargers.

David Tomlinson.