This 50-500mm f/4.5-6.3 APO DG OS HSM Lens for Nikon EOS from Sigma is a zoom lens for digital SLR cameras with a Canon EF or EF-S lens mount. The lens has a standard to ultra telephoto zoom range that is ideal for nature, wildlife, or sports photography. The range translates into an equivalent 75-750mm when used with digital SLR cameras with an APS size chip. The lens is also compatible with full frame cameras. You can even increase your telephoto range by using the Sigma APO teleconverters.