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

Fujifilm X-Mount vs. Leica L-Mount

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

Comparing:
Fujifilm X-Mount
Leica L-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 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)
17.70 mm (0.697 in) 20.00 mm (0.787 in)
Inner Throat Diameter
40.70 mm (1.602 in) 51.60 mm (2.031 in)
Bayonet Tabs
3 locking tabs with counter-clockwise mount twist 4 asymmetrical stainless steel locking tabs (high mechanical rigidity for cinema primes)
Electronic Interface
10 contact pins (opened to third parties in 2020: Tamron, Sigma, Voigtländer, Viltrox) 8 gold-plated electronic spring contacts (standardized cross-manufacturer protocol)
Camera Systems
Fujifilm X-T5, X-H2, X-H2S, X-T30 II, X-S20, X-Pro3, X-E4 Panasonic Lumix S5 II / S5 IIX / S1H / BS1H, Leica SL2 / SL3 / Q series, Sigma fp / fp L, DJI Ronin 4D
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
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)