Fujica X is a type of lens mount developed by Fujifilm in the 1970s for use with AX-1, AX3, AX-5, STX-1, STX-1N, STX-2 single-lens reflex cameras . The bayonet replaced the M42 used on older cameras
The bayonet lock rotates 65 degrees. The working segment is 43.5 mm. [1]
Fujica X-mount lenses
Fujifilm has released a line of twenty lenses covering focal lengths from 16 to 225 mm.