Canon EF lenses on Leicas: Sigma MC-21
The SIGMA MOUNT CONVERTER MC-21 allows SIGMA SA mount and SIGMA’s CANON EF mount interchangeable lenses to be mounted on L-mount cameras
Fast and accurate AF
Tripod mount included
Exif data inclusion
Sigma is part of the Leica L-Mount consortium, so Leica must have agreed to this. You have to go 'way back to the original screw-to-bayonet M adapters, which Leica introduced in the 1950's, to find such a game-changing lens adapter. But even then, other screw-mount lens brands were never mentioned or endorsed by Leica. To my knowledge this is the first time that Leica has endorsed an adapter to use Canon lenses on Leica bodies.