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

Fujifilm X-Mount vs. Sony E-Mount

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

Comparing:
Fujifilm X-Mount
Sony E-Mount

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 →

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)
17.70 mm (0.697 in) 18.00 mm (0.709 in — distance from lens mount mating surface to sensor plane)
Inner Throat Diameter
40.70 mm (1.602 in) 46.1 mm (1.815 in)
Bayonet Tabs
3 locking tabs with counter-clockwise mount twist 3 asymmetrical locking tabs with clockwise twist lock
Electronic Interface
10 contact pins (opened to third parties in 2020: Tamron, Sigma, Voigtländer, Viltrox) 10 gold-plated leaf contact pins (supports real-time eye-AF tracking, OSS, active lens breathing compensation)
Camera Systems
Fujifilm X-T5, X-H2, X-H2S, X-T30 II, X-S20, X-Pro3, X-E4 Sony A7 / A9 / A1 series, FX3 / FX6 cinema lines, A6000-series APS-C bodies
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
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)