On April, 1954 was delivered at GOI in Leningrad a liliput lens called Helios-57 9mm f/3,5,
whose weight was a mere 1,5gr but at the same time it showed a sophisticated 6 elements
Gauss formula plus a plate glass, able to clutch-out some 85 lines per mm! This jewel of miniaturization
was fitted on some micro-spy cameras reportedly used by KGB; one of the most interesting
and cute among them is a true panoramic camera with a spring-driven tilting lens (the same
Helios-57) fitted into a 12mm diameter drum: a true masterpiece milled from solid aluminum
and able to cover 80° on the diagonal of the well-known 8x11mm Minox format; only three
exemplars are know to exist and the acution prices boost to very high rate
courtesy Mario Cavina:
http://www.luciolepri.it/lc2/marcocavina/articoli_fotografici/Helios_57_micropanoramic_camera/00_pag.htm
Image cridits:Westlicht Photographica Auction