Distagon
Distagon is the name for a certain type of photographic lens and a brand of the Carl Zeiss company (Oberkochen). It is retro-focus lenses, so strongly asymmetrical wide-angle lenses in which the focal distance greater than the focal length is. This is necessary for SLR cameras so that the mirror has the necessary freedom of movement to the rear lens.
Well-known camera manufacturers such as Hasselblad and Rollei have or carried Distagon lenses in their lens range. First, the Distagon 5,6 / 60 appeared in 1953 for the Hasselblad 1000 F, recalculated for the Hasselblad 500 C in 1957. The Distagon 4/35 was also calculated for the Contarex in 1957, the Distagon 4/60 for the Hasselblad 500 C in 1959, and the Distagon in 1960 4/55 for the wide-angle Rolleiflex, 1961 the Distagon 2.8 / 25 for the Contarex, 1962 the Distagon 4/50 for the Hasselblad 500 C and the Distagon 2/35 for the Contarex. The development continued, the first Distagon 4/18 was calculated for the Contarex in 1966, the first Distagon 4/40 for the Hasselblad 500 C in 1967.