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

Canon EF vs. Sony E-Mount

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

Comparing:
Canon EF
Sony E-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 Sony E-Mount (introduced in 2010 for NEX mirrorless and expanded in 2013 to 35mm full frame as FE) is a 3-tab bayonet lens mount featuring a 18.0 mm Flange Focal Distance (FFD), a 46.1 mm throat diameter, and a 10-pin high-speed electronic interface. It is the most widely adopted open third-party full-frame mirrorless mount in the photographic industry.

View full Sony E-Mount spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Flange Focal Distance (FFD)
44.00 mm (1.732 in) 18.00 mm (0.709 in — distance from lens mount mating surface to sensor plane)
Inner Throat Diameter
54.00 mm (2.126 in) 46.1 mm (1.815 in)
Bayonet Tabs
3 locking tabs with clockwise twist 3 asymmetrical locking tabs with clockwise twist lock
Electronic Interface
8 gold-plated electronic contacts (expanded to 11 pins on EF super-telephoto lenses for teleconverters) 10 gold-plated leaf contact pins (supports real-time eye-AF tracking, OSS, active lens breathing compensation)
Camera Systems
Canon EOS-1D X Mark III, EOS 5D Mark IV, EOS 6D II, EOS Rebel series, Cinema EOS C300/C500 Sony A7 / A9 / A1 series, FX3 / FX6 cinema lines, A6000-series APS-C bodies
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)
Full-Frame vs APS-C
FE lenses cover 36×24 mm full frame; E lenses cover APS-C (auto-crops on full-frame bodies)
Third-Party Protocol License
Open disclosure to lens manufacturers (Sigma, Tamron, Zeiss, Samyang, Voigtländer)