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

Canon EF vs. Leica L-Mount

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

Comparing:
Canon EF
Leica L-Mount

The Canon EF Mount (introduced in 1987 for the EOS autofocus SLR system) revolutionized photographic camera design as the first 100% all-electronic lens mount, eliminating all mechanical aperture linkages and autofocus drive shafts. Featuring a 44.0 mm Flange Focal Distance and a large 54.0 mm throat diameter, over 150 million EF lenses were manufactured over 33 years.

View full Canon EF spec sheet →

The Leica L-Mount (developed by Leica Camera in 2014 and formalized under the L-Mount Alliance with Panasonic, Sigma, DJI, and Leitz Cine in 2018) is a 4-tab bayonet mount featuring a 20.0 mm Flange Focal Distance, a 51.6 mm throat diameter, and a robust stainless steel clamping mechanism covering both full frame and APS-C formats.

View full Leica L-Mount spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Flange Focal Distance (FFD)
44.00 mm (1.732 in) 20.00 mm (0.787 in)
Inner Throat Diameter
54.00 mm (2.126 in) 51.60 mm (2.031 in)
Bayonet Tabs
3 locking tabs with clockwise twist 4 asymmetrical stainless steel locking tabs (high mechanical rigidity for cinema primes)
Electronic Interface
8 gold-plated electronic contacts (expanded to 11 pins on EF super-telephoto lenses for teleconverters) 8 gold-plated electronic spring contacts (standardized cross-manufacturer protocol)
Camera Systems
Canon EOS-1D X Mark III, EOS 5D Mark IV, EOS 6D II, EOS Rebel series, Cinema EOS C300/C500 Panasonic Lumix S5 II / S5 IIX / S1H / BS1H, Leica SL2 / SL3 / Q series, Sigma fp / fp L, DJI Ronin 4D
Internal Actuators
Internal USM (Ultrasonic Motor) in lens body + internal electromagnetic aperture diaphragm (EMD)
Variants
EF (Full Frame), EF-S (APS-C with rubber bumper back-focus extension), EF-M (discontinued APS-C mirrorless)
Alliance Partners
Leica Camera AG, Panasonic Corporation, Sigma Corporation, DJI, Ernst Leitz Wetzlar GmbH, Blackmagic Design
Coverage Formats
SL (35mm Full Frame 36×24 mm) and TL (APS-C 23.6×15.7 mm)