The Sigma 50mm f/1.4 DG HSM Art Lens for Leica L-Mount is a normal-length prime that is designed to achieve high optical performance, through the combination of using three Special Low Dispersion glass elements, and one molded glass aspherical element. These elements, paired with an advanced optical design, work to reduce flare and chromatic aberrations in order to produce high image clarity and sharpness. The lens' large diameter & floating system help to correct for vignetting to provide maintained peripheral brightness. A Super Multi Coating has been applied to the lens to reduce flare and ghosting, and to produce higher contrast and color fidelity. Its bright f/1.4 maximum aperture works with a rounded nine-blade diaphragm to improve selective focus & shallow depth of field imaging (with smooth bokeh). Its Hyper Sonic Motor produces smooth, quick, and quiet autofocus performance with full-time manual focus override. The physical design uses Thermally Stable Composite material for durability, and a brass bayonet mount, which also offers durability, as well as mounting precision.