Characterized by its apochromatic designation, the APO-Summicron-M 90mm f/2 ASPH. from Leica is a fast short telephoto lens designed for M-mount rangefinder cameras. As an apochromat, this lens utilizes a pair of anomalous partial dispersion glass elements to virtually eliminate color fringing and chromatic aberrations for notable clarity and color accuracy. One aspherical element and two high refractive index glass elements are also used to control spherical aberrations and distortion, as well as to maintain a high degree of sharpness. Its manual focus design permits working with subjects as close as 3.3′ away and its compact design also incorporates a built-in extendable lens hood to shield the front element.