"Sigma APO 120-300mm F2.8 DG OS HSM (137-101) Conventionally, large aperture lenses for 300mm F2.8 have been loved by professional users due to their brilliant capability of depiction and bright aperture value. It has established a solid standpoint in the world of photography. Based on the concept that turning a 300mm F2.8 lens into zoom lens would enable photographers to expand the scope of shooting, we have developed 120-300mm F2.8 lenses and released them into the market. It is not simple to decide on a composition with a 300mm lens. Especially for sports and theatrical shows, shooting positions are almost always fixed and changing lenses could lead to missed photographs. By adding a zoom function with the large aperture 300mm F2.8 lens, it no longer requires other interchangeable lenses and rotation of the zoom ring will offer excellent framing. In other words, when conditions are difficult, this high-performance lens gives you more scope to express yourself in the shots you take. Sports line lenses deliver high action-capture performance Sigma is organizing all its interchangeable lenses into three product lines; Contemporary, Art and Sports. While offering sophisticated optical performance and expressiveness, our Sports line lenses deliver high action-capture performance, enabling photographers to get exactly the shots they want. With their high-level optical performance and expressive power, these lenses can capture fast-moving subjects, eve n|Designed for use with full frame digital SLR cameras. May also be used with smaller APS-c size sensors|Splash-proof feature protects the lens from the effects of harsh weather conditions|Offers Sigma's OS System (Optical Stabilization) allowing handheld photography even in low-light situation|HSM (Hyper-Sonic Motor) ensures a quiet and high-speed auto focus|FLD glass elements with performance equal to fluorite glass for compensate for color aberration"