this 50-100mm f/1.8 DC HSM Art Lens from Sigma is designed for APS-C-format Canon EF-mount DSLRs, and provides an 80-160mm equivalent focal length range. The bright 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. Complementing the versatile telephoto range is a sophisticated optical design that incorporates three F Low Dispersion elements, one Special Low Dispersion element, and one high-refractive index, high-dispersion glass element. This combination of low dispersion designs works to noticeably reduce chromatic aberrations and color fringing throughout the zoom range, as well as deliver a high degree of contrast and clarity. Additionally, a Super Multi-Layer Coating has been applied to lens elements to reduce lens flare and ghosting to benefit working in strong lighting conditions. An unprecedented combination of focal length and speed, this 50-100mm f/1.8 lens offers a variety of favored telephoto perspectives in combination with a flexible maximum aperture.