# item.guide
Side-by-Side Comparison Lens Mounts

Canon RF vs. Micro Four Thirds Mount

Comparing 2 standards across 9 specifications. 9 key differences identified.

Comparing:
Canon RF
Micro Four Thirds Mount

The Canon RF Mount (introduced in 2018 for the EOS R system) is a 3-tab full-frame mirrorless bayonet mount featuring a 20.0 mm Flange Focal Distance, a wide 54.0 mm inner throat diameter, and an advanced 12-pin high-speed data bus. Retaining the large 54mm diameter of the classical EF mount, it enables ultra-fast aperture lenses such as the RF 28-70mm f/2L and 50mm f/1.2L.

View full Canon RF spec sheet →

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.

View full Micro Four Thirds Mount spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Flange Focal Distance (FFD)
20.00 mm (0.787 in) 19.25 mm (0.758 in)
Inner Throat Diameter
54.00 mm (2.126 in — identical to legacy Canon EF mount) 38.00 mm (1.496 in)
Bayonet Tabs
3 asymmetrical stainless steel bayonet tabs with clockwise mounting twist 3 symmetrical stainless steel tabs
Electronic Interface
12 contact pins (high-bandwidth bidirectional bus for lens control ring and Coordinated IS up to 8 stops) 11 gold-plated electronic contacts (shared protocol between OM System and Panasonic)
Camera Systems
Canon EOS R5 / R6 / R3 / R8 / R, Cinema EOS C70 / C80 / C400, APS-C EOS R7 / R10 OM System OM-1 Mark II, Panasonic Lumix GH6 / G9 II, Blackmagic Pocket Cinema Camera 4K, DJI Inspire 3 X9 MFT
Legacy Adaptability
100% native AF/IS compatibility with all Canon EF/EF-S lenses via Canon EF-EOS R adapter (24mm spacer)
Lens Control Ring
Physical programmable control ring on all native RF lenses (aperture, ISO, exposure compensation)
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