Fujica X-mount
The Fujica X-mount was a lens mount created by Fujifilm in the late 1970s and early 1980s for the new Fujica SLR lineup: AX-1, AX-3, AX-5, AX Multi, STX-1, STX-1N, STX-2, MPF105X, MPF105XN. It replaced the M42 screw mount used on their earlier SLRs.
The mount is a bayonet type, with a 65° clockwise lock, and a flange focal distance of 43.5 mm.
With the advent of autofocus, the Fujica series of 35 mm SLR cameras was discontinued in 1985, rendering this mount obsolete. Fuji would return to the SLR market in 2000 with a series of digital SLR cameras starting with the FinePix S1 Pro, but these were based on Nikon designs and used the autofocus version of the Nikon F-mount.
Fujifilm introduced a line of twenty-seven X-Fujinon lenses with this mount (as well as three Fujinar lenses):