Specifications of International Camera mount Threads

Lens mount Threads

In photography a standardized adaption device for the changing of lenses which works independent from the manufacturer is called screw thread or lens thread. Screw threads are the forerunners of the bayonet connectors, which dominate the market nowadays. Screw threads were mainly used upto the 1980s. However, the M42-screw thread still offers a low-priced alternative to the analoguos mirror reflex camera with high-quality lenses.


M39-Screw Thread M39 x 26Gg
The M39-Screw Thread - also called Leica L-Mount - was used in miniature cameras since the 1930s. Companies that offer these mounts are e.g. Leica, Voigtländer, Canon and Ricoh. For this thread sporadically high-quality lenses are still available today.

M40-Screw Thread
The M40-Screw Thread is a quite rare thread. It was mainly used in the 1930s. E.g. the Praktiflex and Praktiflex II of the brand Praktika resp. Pentacon had this lens connection. Some CCD-camaras still use the M40-thread nowadays.

M42-Screw Thread M42 x 1.0
M42 is the term for a standardized screw thread that was used for cameras of e.g. Praktica, Voigtländer, Fujica ST, Ricoh and Pentax. M42 is the successor of the older M39-screw thread and was developped in a time when the manufacturer's didn't yet try to tie the users down to their own company's lens bayonets.

T2-screw thread M42 x 0.75
T2 is an old Tamron standard. There are multiple adapters available for T2, from T2 to other sizes and vice versa. For a number of applications the T2-mount has become standard, e.g. for microscopes, telescopes and slide duplicators.

C-Mount 1" x 32 TPI UN 2A
Standard connection of lenses for CCD-cameras, with a standard mount thread (at the lens: male thread 1"-32UN2A) with a standard flange focal distance of 17.526 mm.

CS-Mount 1" x 32 TPI UN 2A
Is equal to C-Mount apart from the standard flange focal. The CS-mount has a flange focal distance of 12.5 mm. The CS-Mount standard is the "younger" standard, which meets the demand for shorter lengths.

Tripod Threads DIN 4503 / ISO 1222

1/4" - 20 UNC
This thread is used for rangefinder camera, roll film cameras (also DSLRs) up to medium format cameras, quick release plates and panoramic heads.

3/8" - 16 UNC
Some medium format cameras and almost all large size cameras as well as most of the connectors between tripods and panoramic heads use this thread.

Filter Mounts

On the lens is the internal thread, on the filter the external thread, both threads are chamfered and have a flat stop on the outside. 1.5 to 2 turns are sufficient for fastening. The M stands for the metric dimension in millimetres of the outside diameter, followed by the x the pitch is given. The designation "E"nn is found on lenses, this "E" is derived from "E"inschraubgewindedurchmesser in screw thread diameter. Often only the filter diameter, but not the pitch is given, this is usually sufficient to clearly determine the filter thread.

Thread with 0.50 mm pitch:

M 19 x 0.5 (occasionally)
M 24 x 0.5 (occasionally)
M 25.5 x 0.5 (occasionally)
M 27 x 0.5 (often, video)
M 28.5 x 0.5 (Astronomie 1.25" = 31.75 mm diameter)
M 30.5 x 0.5
M 34 x 0.5 (occasionally)
M 35 x 0.5 (occasionally)
M 35.5 x 0.5 (often, video)
M 36.5 x 0.5
M 37 x 0.5
M 37.5 x 0.5
M 39 x 0.5 (video)
M 40 x 0.5 (occasionally)
M 40.5 x 0.5 (often, video)
M 41 x 0.5 (occasionally)
M 43 x 0.5 (occasionally)
M 45 x 0.5

Thread with 0.60 mm pitch:

M 28.5 x 0.60 (astronomy 1.25")
M 48 x 0.60 (astronomy 2")

Thread with 0.75 mm pitch:

M 25 x 0.75
M 27 x 0.75 (occasionally)
M 28 x 0.75 (occasionally)
M 28.5 x 0.75 (occasionally)
M 30 x 0.75
M 30.5 x 0.75
M 37 x 0.75
M 38 x 0.75 (occasionally)
M 43 x 0.75
M 46 x 0.75
M 48 x 0.75 (also astronomy 2")
M 49 x 0.75 (often)
M 52 x 0.75 (very often)
M 55 x 0.75 (often)
M 58 x 0.75 (very often)
M 60 x 0.75
M 62 x 0.75 (very often)
M 67 x 0.75 (very often)
M 69 x 0.75
M 72 x 0.75 (very often)
M 75 x 0.75 (rarely)
M 77 x 0.75 (very often)
M 82 x 0.75 (often)
M 100 x 0.75

Thread with 1.00 mm pitch:

M 86 x 1 (often, also known as C 86)
M 95 x 1 (also known as C 95)
M 100 x 1
M 105 x 1 (also known as C 105)
M 122 x 1

Thread with 1.50 mm pitch:

M 112 x 1.5