The Leica L-Mount
It’s got 4 lobes, 10 electronic contacts… and legs! It’s not really a “universal mount” but it transports Leica into the mirrorless future.
When Leica launched the L-mount in 2014 with the debut of the APS-C-format Leica T ((Typ 701) they initially called the T-mount. It officially became the L-mount when Leica announced the fully compatible full-frame version of the L-mount with the advent of the landmark Leica SL in late 2015. Understandably the press focused on these sleek new cameras bristling with innovative features and generally mentioned the L-mount only in passing. After all, the new high-performance 16MP Leica T featured a user-friendly twin-dial control system complemented with a large 3.7-inch touchscreen interface, a minimalist “unibody” hewn out of a solid billet of aluminum, offered an optional 2.63m-dot EVF with a built-in GPS unit, and offered a line of exciting new Leica lenses including an 18-56mm f/3.5-5.6 and a 23mm (35mm equivalent) f/2.
About a year later Leica brought forth the elegant pro-aimed 24MP Leica SL (Typ 601), its first non-rangefinder-style full frame mirrorless camera. It features an advanced Maestro II image processor that enables 11 fps full-res bursts (7 fps with AF), a native ISO range of 50-50000, and 4K video recording, all built into a robust weather-sealed body with dual SD card slots. Press coverage also highlighted the camera’s impressive specs and its mouthwatering array of pricey full-frame L-mount lenses including: the Vario-Elmarit-SL f/2.8–4 24–90mm ASPH., APO-Vario-Elmarit-SL f/2.8–4 90–280mm, Super-Vario-Elmar-SL f/3.5-4.5 16-35mm ASPH., and the magnificent Summilux-SL f/1.4 50mm ASPH designed by Peter Karbe.
Panasonic full frame Lumix DC-S1 with 24-105mm Panasonic L-mountlens
Sigma MC-21 Converter for mounting Canon EF lenses on L-mount cameras
Leica T (Typ 701) body showing APS-C T-mount
Despite its somewhat underwhelming introduction the Leica L-mount is perhaps the most ingenious, forward-looking, and influential lens mount Leica has designed since the landmark M-mount of 1954 that revolutionized 35mm rangefinder photography and (with the addition of electronic coding) is still going strong. With the announcement of the cooperative L-mount Alliance of Leica, Panasonic, and Sigma in September 2018 Leica has ensured that it will maintain an active and influential presence as the digital mirrorless future unfolds. The L-mount can accommodate lenses that are compatible with Leica TL, CL, and SL camera systems, and there are Leica adapters allowing M- and R-mount Leica lenses to be used on L-mount cameras as well as proprietary adapters (from Novoflex, Fotodiox, Kipon, amd others) for other lens mount systems such as Nikon and Canon. To its credit, Leica designed the L-mount with maximum optical flexibility in mind and that’s why top-tier manufacturers like Panasonic and Sigma have signed onto it.
Leica 16-35mm f3.5-4.5 Super Vario-Elmar ASPH full-frame L-mount lens
Leica SL (Typ 601) bdy showing full-frame L-mount
Sigma 135mm f1.8 DG HSM Art lens for full-frame L-mount
Beautifully finished in stainless steel, the 4-lobed Leica L-mount with an array of 10 inboard gold-plated contacts arrayed along the top was specifically developed by Leica Camera AG for interchangeable lens autofocus digital cameras. It has a wide inner diameter of 51.6mm enabling maximum flexibility for optical designers in configuring a variety of wide-aperture lenses, and a very short (20.0mm) flange depth (mount to sensor distance) that enables more compact lenses, especially wide-angles, to be designed using the latest technology, and also facilitated the use of lenses from other systems using straightforward adapters that don’t require optical elements to achieve infinity focus. L-mount lenses are produced in two versions, an APS-C version (TL) and a full-frame version (SL), both of which are mechanically and mechanically compatible. When TL lenses are mounted on a full-frame L-mount (SL) camera, the camera automatically switches to crop mode and captures an APS-C-size image section cropped from the center of the full-frame sensor. When a full-frame (SL) L-mount lens is used on an APS-C format L-mount camera it will function normally, providing a 1.5x cropped field of view, thus increasing the effective focal length of the lens by a factor of 1.5.
L-Mount on Full Frame Leica-SL
Top-of-the-line Panasonic Lumix S1R body with full-frame L-mount
Leica 90-280mm f2.8-4 APO-Vario-Elmarit ASPH full-frame Elmar lens
The L-mount Alliance licenses Sigma (a leading independent maker of high quality lenses and cameras) and Panasonic (an electronics giant whose imaging division has made Leica branded cameras and has Leica branded lenses on its cameras) to use an upgraded version of the L-mount for their own products, opening the way for a more extensive cross-branded system of fully compatible cameras and lenses. According to the official announcement, the Alliance enables the partners to “make use of the L-mount standard developed by Leica for their own developments, and to offer both cameras and lenses using this mount, with full compatibility among the three companies’ products.” The arrangement is a great tribute to Leica’s leadership and expertise.
One indication of the dynamic nature of the L-mount Alliance is the way it’s already creating innovations that enhance its real world performance and market expansion. As Sigma’s CEO Kazuto Yamaki noted, “The L-mount system we’re using is not exactly the same as the original one. We updated (tweaked) it a little to work better when these lenses are used with lens adapters.” Sigma also announced that they’re planning to launch a full-frame L-mount mirrorless camera by late 2019 or early 2020 that incorporates its signature 3-layer Foveon sensor that captures full color information at each pixel point as well as L-mount adapters for Sigma SA and Canon EF lenses. At the same time Panasonic announced the high-spec Panasonic S1 and S1R full-frame L-mount mirrorless cameras, the latter the flagship of the line with a 47.3MP MOS Sensor, a hi-res OLED EVF, a 3.2-inch hi-res Triaxial Tilt Touchscreen ad 4K Video at 60 fps. Panasonic also unveiled 3 impressive full frame L-mount Panasonic Lumix S Pro lenses, a 50mm f/1.4, 70-210mm f/4 O.I.S, anf 24-105mm f/4 Macro O.I.S., the latter pair with built-in image stabilization, and will launch 7 more by 2020. In total 6 new L-mount lenses and 39 new native lenses are slated to be on the market by 2020 as a result of the L-mount Alliance.
The L-Mount Lens Scene
As of this writing Leica offers 15 exquisite L-mount lenses, including 4 APS-C primes ranging from the 18mm f2.8 Elmarit-TL ASPH to the 60mm f/2.8 APO-Macro-Elmarit ASPH, a trio of APS-C zooms ranging from the 11-23mm Super-Vario-Elmar ASPH to the 55-135mm f/3.5 Leica APO-Vario-Elmar ASPH, 5 glorious full-frame primes including the 50mm f1.4 Summilux-SL ASPH and 35mm, 50mm, 75mm, and 90mm f/2 APO-Summicron SL lenses and 3 magnificent zooms, the 16-35mm f/3.5-4.5 Super-Vario-Elmar-SL ASPH, 24-90mm f/2.8-4 Vario-Elmarit SL ASPH, and the imposing 90-280mm f/2.8-4 APO-Vario-Elmarit SL.
Sigma has announced a complete new line of full-frame L-mount Sigma lenses in its acclaimed Art line ranging from the Sigma 14mm f/1.8 DG HSM Art to the Sigma 135mm f/1.8 DG HSM Art, including the 70mm f/2.8 DG MACRO Art, and an amazing collection of no less than 8 DG HSM Art f/1.4s, a 20mm 24mm, 28mm, 35mm, 40mm 50mm. 85mm and a 105mm! You can rest assured that Leica and Panasonic will be inspired by this emerging optical extravaganza and will be developing their own L-mount alternatives, thus enriching the whole integrated system.
In the end, it all gets back to Leica’s original ingenious and brilliantly executed L-mount, which was designed to be robust, optically flexible, future-proof, and precise. It’s made of stainless steel for maximum strength and durability and its 4 flange segments ensure firm, exact lens seating and perfect positioning, with no wobble or canting. The standardized contact strip ensures trouble-free communication between the lens and the camera’s electronics, and allows for facile firmware updates to accommodate future technological advances. Above all, the L-mount system and the L-mount Alliance are good for consumers because it gives them more choices in achieving their ultimate goal—capturing great images.
Personally I love the idea of being able to mount a Sigma Art lens on, say the latest Panasonic full frame mirrorless or Leica SL, but what really rings my chimes is being able to shoot with my classic Leica M- or R-mount lens on any L-mount mirrorles camera or to mount an SL-series L-mount lens on my latest heartthrob, the snazzy Leica CL. Optical flexibility is one of the prime advantages of mirrorless cameras, and kudos to Leica for leading the charge.