Sigma firmware update adds programmable focus rings for eight L-mount lenses

Sigma has given eight of its L-mount lenses a practical firmware boost that matters most in daily shooting, not on a spec sheet. The update lets photographers assign custom functions to the focus ring while the lens is in autofocus, reverse focus-ring direction in manual focus, and display aperture as a T-stop during video recording.

For shooters who keep lenses in AF most of the time, that first change is the standout. A ring that usually sits idle can now become a configurable control surface, which means a familiar lens can handle more without adding a single new button or dial. The focus-direction option also answers a long-running muscle-memory problem for photographers moving from Nikon bodies, where the rotation convention differs from much of the rest of the industry. For video work, the T-stop readout is a smaller change, but one that gives Lumix users and other hybrid shooters a more consistent exposure language on set.

Sigma rolled the firmware out on April 23, 2026, and the list covers a broad slice of its L-mount lineup. The eight supported lenses include the 20mm F2 DG DN | Contemporary and its black and silver version, the 24mm F1.4 DG DN | Art, the 24mm F2 DG DN | Contemporary and its black and silver version, the 35mm F1.4 DG DN | Art, the 50mm F1.2 DG DN | Art, and the 500mm F5.6 DG DN OS | Sports. Depending on the lens, Sigma lists firmware versions such as Ver.1.2 and Ver.1.3.

The company said the new features work only on supported cameras, so this is not a universal L-mount change. Sigma also laid out two update paths: install the firmware in camera from each product’s download page, or use the SIGMA USB DOCK UD-11 with Sigma Optimization Pro. UD-11 owners need to update Sigma Optimization Pro to the latest version before applying the lens firmware.

This is not a one-off tweak. Sigma released a similar L-mount firmware package on January 23, 2026, with the same focus-ring and T-stop functions for another set of lenses, which points to a broader support pattern rather than a single headline update. That matters inside the L-Mount Alliance, the 2018 partnership announced by Leica Camera AG, Panasonic and Sigma in Cologne, because the ecosystem was built around shared hardware that can keep evolving after purchase. For L-mount users, that is the real story here: the lens they already own just became more flexible, and that flexibility reaches into stills, video and muscle memory all at once.