Leica APO-Summicron-M 50mm f/2.0 ASPH Lens APO-Summicron-M 50mm f/2.0 ASPH Lens, 50mm Focal Length, Aperture: f/2.0 - f/16, No Image Degradation At f/5.6, Angle of View: 47 / 40 / 27 Degrees, 8 Elements In 5 Groups, Rear