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C mount

A C-mount is a type of lens mount commonly found on 16mm movie cameras, closed-circuit television cameras, and trinocular microscope phototubes.

C-mount lenses provide a male thread which mates with a female thread on the camera. The thread is nominally 1 inch in diameter, with 32 threads per inch, designated as "1-32 UN 2A" in the ANSI B1.1 standard for unified screw threads. The flange focal distance is 17.526 mm (0.69 inches) for a C-mount, 12.52 mm for the otherwise identical CS-mount.

Lenses made originally for TV cameras may not always fit movie cameras, as some lack provision to focus or set exposure, as the video cameras could perform these functions by other means. Also note that the back element of some video lenses may protrude too far from the mount, and would interfere with the shutter or reflex finder mechanisms in a movie camera.

The letter "C" is said to stand for "cine", the original application being movie camera lenses.

See also

• T-mount

References

• ISO 10935:1996, "Optics and optical instruments -- Microscopes -- Interfacing connection type C"

External links

• Making Digital Camera Microscope Adapters. The section "Understanding C-Mount and CS-Mount Standard Mechanics, Optics, and Cameras" discusses the standards and custom machining of C-mount apparatus.