Canon EF 50mm f/1.4 USM Prime Lens for Canon DSLR CameraProduct Description: By optically distributing power with a Gauss type design and two high refraction glass lenses, flare at maximum aperture is minimized and astigmatism is greatly reduced. Moreover, improvements in the quality of the focused image and the beautiful natural blur of the background are simultaneously achieved. Use of a Micro USM (Micro Ultrasonic Motor) provides fast, silent auto focusing, as well as full time manual focus. The color