Common industrial camera mounts include C-mount, CS-mount, F-mount, M72-mount, M95-mount, and others. Except for the F-mount, most mounts are defined by their thread specifications and have a fixed flange back distance. The F-mount uses a bayonet connection style.

Take the C-mount as an example. It features a 1-inch diameter thread with 32 threads per inch. It is compatible with industrial cameras using sensors up to 4/3-inch (diagonal approx. 22.6 mm). The flange back distance of a C-mount camera is 17.526 mm, and it must be used with C-mount lenses, as shown in the diagram below.

Important note: For proper focusing, the lens’s designed flange back distance must be greater than or equal to the camera’s flange back distance. For instance, a CS-mount lens cannot be used on a C-mount camera, as it will fail to focus correctly.