M42 Screw Mount vs. Micro Four Thirds Mount
Comparing 2 standards across 12 specifications. 12 key differences identified.
The M42 Screw Mount (also known as the Universal Screw Mount or Praktica/Pentax Thread, standardized under DIN 4503) is a standardized metric threaded lens interface featuring an M42 × 1.0 mm thread pitch and a 45.5 mm Flange Focal Distance. Popularized by Asahi Pentax Spotmatic and Soviet Helios-44 lenses, it is the most adapted vintage manual lens standard in mirrorless photography.
The Micro Four Thirds Mount, introduced in 2008 by Olympus and Panasonic as the first mirrorless system built as a dedicated open standard (rather than an adapted rangefinder mount, as with the earlier 2004 Epson R-D1), features a 19.25 mm Flange Focal Distance, a 38.0 mm throat diameter, and an 11-pin all-electronic bayonet interface. Governing an open consortium, it is used across OM System, Lumix, Blackmagic Design, and DJI aerial cameras.
Specification Comparison Table
12 Parameters| Parameter / Spec | ||
|---|---|---|
|
Flange Focal Distance (FFD)
|
45.50 mm (1.791 in) | 19.25 mm (0.758 in) |
|
Thread Dimensions
|
M42 × 1.0 mm metric thread (42.0 mm diameter with 1.0 mm thread pitch) | — |
|
Mounting Style
|
Direct screw-in thread (approx. 2 to 3 full revolutions to seat against flange) | — |
|
Aperture Pin Mechanism
|
Center spring-loaded pin pressed by camera stop-down lever to close iris during exposure | — |
|
Benchmark Cameras & Lenses
|
Pentax Spotmatic (Super-Takumar / SMC Takumar), Praktica L-series, Zenit-E (Helios-44-2 58mm f/2), Carl Zeiss Jena | — |
|
Mirrorless Adaptability
|
Adapted seamlessly to Sony E, Canon RF, Nikon Z, L-mount, Fuji X, and MFT via inexpensive passive aluminum rings | — |
|
Inner Throat Diameter
|
— | 38.00 mm (1.496 in) |
|
Bayonet Tabs
|
— | 3 symmetrical stainless steel tabs |
|
Electronic Interface
|
— | 11 gold-plated electronic contacts (shared protocol between OM System and Panasonic) |
|
Historic Milestone
|
— | First mirrorless system built as a dedicated open standard, launched with the Panasonic Lumix G1 (2008) -- the earlier 2004 Epson R-D1 was a mirrorless interchangeable-lens camera, but on an adapted rangefinder mount, not a purpose-built open standard |
|
Consortium Members
|
— | OM Digital Solutions (Olympus), Panasonic, Blackmagic Design, DJI, Sharp, Voigtländer, Laowa |
|
Camera Systems
|
— | OM System OM-1 Mark II, Panasonic Lumix GH6 / G9 II, Blackmagic Pocket Cinema Camera 4K, DJI Inspire 3 X9 MFT |