 It is a high performance telephoto lens most often used for sports and wildlife photography.When used with a Canon APS-C (1.6× crop) DSLR camera or APS-H (1.3× crop), the field of view of this lens is equivalent to a 160–640 mm on an APS-C sensor, or 130–520 mm on an APS-H sensor.This is due to the crop factor inherent with APS-C or APS-H sensor digital SLR cameras.