Standardized interface for the mounting of lenses, described in ISO 10935 (1996-12) Optics and optical instruments – Microscopes – Interface Type C
Standard interface for mounting of lenses.
The diameter of the thread is 1 “(one inch) and there are 32 threads to 1” in length.
The distance between the mechanical stop of the lens and the sensor in air is 17,526 mm
This is about 5mm more than for CS-mount lenses. C-mount lenses can be used with a 5mm extension ring (“C- to CS-mount adapter”) with CS-mount cameras.
CS-mount lenses however can not be used with C-mount cameras.
C-mount lenses are usually used for factory automation lenses.