Presenting a favored focal length for portraiture, the APO-Summicron-SL 90mm f/2 ASPH. from Leica is an optically refined short telephoto prime designed for full-frame L-mount mirrorless cameras. Complementing the comfortable focal length is a bright f/2 maximum aperture that suits working in low-light conditions and also affords great control over depth of field for isolating subject matter. The lens' apochromatic optical design uses anomalous partial dispersion glass to suppress color fringing and chromatic aberrations for high clarity and color accuracy, and one aspherical element is also featured to reduce spherical aberrations for improved sharpness. Multi-layer coatings have also been applied to limit flare and ghosting for increased contrast when working in strong lighting conditions. Complementing the optical assets is a Dual Syncro Drive stepping motor, which delivers fast and quiet autofocus performance, and a floating elements system maintains consistent imaging quality throughout the focusing range. Additionally, an AquaDura coating has been applied to the exposed elements and seals have been incorporated in the lens design to benefit working in harsh environmental conditions.