Leica SUMMICRON-M 2 50 mm black. The Leica Summicron-M 1:2/50 is distinguished not only by its compact and proven optical design but also by its natural perspective. Even at its widest aperture, the optical calculations enable outstanding image quality and excellent contrast across the entire image field. Technical details: The balanced design makes this ideal standard lens the first choice in every respect – image quality, speed, size, and weight. Stopping down to f/2.8 or f/4 results in only a minimal increase in contrast. Distortion is extremely low and practically invisible.