Leica L-Mount (L-Mount Alliance)
Direct Answer
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.
Source: L-Mount Alliance Standard Specification (Leica, Panasonic, Sigma, DJI, Leitz Cine)
Specs
| Flange Focal Distance (FFD) | 20.00 mm (0.787 in) |
| Inner Throat Diameter | 51.60 mm (2.031 in) |
| Bayonet Tabs | 4 asymmetrical stainless steel locking tabs (high mechanical rigidity for cinema primes) |
| Electronic Interface | 8 gold-plated electronic spring contacts (standardized cross-manufacturer protocol) |
| 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) |
| Camera Systems | Panasonic Lumix S5 II / S5 IIX / S1H / BS1H, Leica SL2 / SL3 / Q series, Sigma fp / fp L, DJI Ronin 4D |
The L-Mount Alliance Interoperability
Unlike proprietary mounts where third-party lens makers must reverse-engineer autofocus protocols, the L-Mount Alliance shares native lens communication firmware. A Sigma Art lens, Panasonic Lumix S-Pro lens, and Leica APO-Summicron lens communicate natively with identical phase-detection AF and dual-IS stabilization across any alliance body.