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

Canon RF vs. Fujifilm X-Mount

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

Comparing:
Canon RF
Fujifilm X-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 Fujifilm X-Mount (introduced in 2012 for the X-Pro1) is a dedicated APS-C mirrorless bayonet mount featuring a 17.7 mm Flange Focal Distance, a 40.7 mm throat diameter, and a 10-pin electronic interface. Designed exclusively for APS-C image circles, it allows compact lens designs optimized for Fujifilm's proprietary X-Trans CMOS sensors.

View full Fujifilm X-Mount spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Flange Focal Distance (FFD)
20.00 mm (0.787 in) 17.70 mm (0.697 in)
Inner Throat Diameter
54.00 mm (2.126 in — identical to legacy Canon EF mount) 40.70 mm (1.602 in)
Bayonet Tabs
3 asymmetrical stainless steel bayonet tabs with clockwise mounting twist 3 locking tabs with counter-clockwise mount twist
Electronic Interface
12 contact pins (high-bandwidth bidirectional bus for lens control ring and Coordinated IS up to 8 stops) 10 contact pins (opened to third parties in 2020: Tamron, Sigma, Voigtländer, Viltrox)
Camera Systems
Canon EOS R5 / R6 / R3 / R8 / R, Cinema EOS C70 / C80 / C400, APS-C EOS R7 / R10 Fujifilm X-T5, X-H2, X-H2S, X-T30 II, X-S20, X-Pro3, X-E4
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) —
Back Focus Distance
— Minimum rear optical element clearance of 7.5 mm from sensor
Physical Aperture Rings
— Standard mechanical aperture rings with 1/3-stop clicks on XF lenses