Sigma 50-100mm f/1.8 DC HSM Art Lens for Canon EF, Pairing a useful range of telephoto focal lengths with an especially fast design, this Canon EF-mount Sigma 50-100mm f/1.8 DC HSM is an Art-series zoom mixing impressive versatility with advanced optics. The bright f/1.8 constant maximum aperture offers consistent low-light performance throughout the zoom range and also affords greater control over focus placement for shallow depth of field and selective focus applications. The optical design incorporates a series of low dispersion and high-refractive index elements, which help to achieve high clarity and sharpness by suppressing various aberrations, color fringing, and distortion. A Super Multi-Layer Coating has been applied, too, which controls lens flare and ghosting for improved contrast and color accuracy. Balancing the optical merits, this 50-100mm also sports an advanced Hyper Sonic Motor, along with an internal focusing and zoom design, to promote fast, quiet, and precise autofocus performance. Additionally, a tripod collar is integrated into the lens’s design for greater stability when working atop a tripod or monopod.