The
T-mount is a standard
lens mount for
cameras and other optical assemblies. The usual T-mount is a screw mount using a male 42×0.75 (42 mm diameter, 0.75 mm thread pitch) metric thread on the lens with a
flange focal distance of 55 mm and a mating female 42mm thread on a camera adapter or other optical component. This thread form is referred to as
T-thread. (This should not be confused with the
M42 lens mount which is also 42 mm diameter, but has a 1 mm thread pitch.)