21MM SCREW MOUNT LENSES
It is important to note that Leica lenses had their focal lengths specified in millimeters from 1925 to 1928, in centimeters from 1928 to 1970, and again in millimeters from 1971 onwards360.
2.1CM F/4 SUPER ANGULON
The lens code-named SUOON was produced between 1958 and 1963. During this period, as sales of Leica screw-mount cameras declined, Leitz manufactured only 1462 screw mount Super Angulons184.
This first version of the Super Angulon features a rotating chrome mount equipped with dual focusing scales that use red and black numerals. The first Super Angulon design included nine elements and required a special rear lens cap (catalogue Number 14048, code-named OIXMO), to protect the protruding rear elements of the screw mount lenses184.