Leica's R-mount standard zoom — the Vario-Elmar 28-70mm f/3.5 with 3-Cam compatibility.
The Leica Vario-Elmar-R 28-70mm f/3.5 in 3 Cam configuration is a wide-to-standard zoom from Leica's R-mount system with the three-cam coupling required for full metering compatibility with all Leica R body generations. The 3-cam designation is critical for the R system — different body generations required different cam followers.
The lens delivers 28–70mm at f/3.5 constant maximum aperture with Leica R 3-cam bayonet (compatible with all R bodies from Leicaflex SL through R9), manual focus and aperture, and full-frame 35mm coverage. Constant f/3.5 at this focal range is a notable specification.
The '3 Cam' designation is operationally important in the Leica R system: 1-cam lenses work only with early R bodies; 2-cam lenses work with the R3 and later; 3-cam lenses work with all R bodies including the original Leicaflex SL. A 3-cam lens represents the most versatile Leica R configuration.
Verify 3-cam condition — all three cam followers should be present and undamaged. Test zoom and focus ring operation. Inspect element condition and Leica coating quality. Check constant f/3.5 aperture across the zoom range by verifying lens opening at both 28mm and 70mm positions.