Leica's standard R-mount prime — Summicron 50mm f/2 with 3-cam for all R bodies.
The Leica Summicron-R 50mm f/2 (3rd Cam) is a standard prime for the Leica R SLR system at Summicron (f/2) aperture class. The 3rd Cam (3-Cam) enables metering on Leica M bodies via M-Adapter-R in addition to standard R body compatibility. Leica R mount.
f/2 maximum aperture. 50mm focal length (full-frame). 3-Cam coupling (Leicaflex SL, R3–R7, and Leica M via M-Adapter-R). Manual focus via SLR viewfinder. At approximately 320g. 55mm filter thread. Leica R mount.
The Summicron-R 50mm is the standard normal prime for the Leica R system. As with all R-mount lenses, it is used on modern mirrorless cameras via adapters. 3-Cam enables M-body metering — for mirrorless adapted use this is irrelevant. A practical and optically capable standard prime.
On the used market the Leica Summicron-R 50mm f/2 (3rd Cam) is a premium standard prime. Condition checks: 55mm front element, three cam contacts for wear, aperture blade condition, focus ring smoothness. Leica R mount — requires adapter for current cameras.