This EF 50mm f/1.4 USM Lens from Canon is a standard length lens featuring superb quality and portability. Its f/1.4 maximum aperture makes it very effective in low light situations and able to provide shallow depth of field focus. Two high-refraction lens elements and Gaussian optics eliminate astigmatism and suppress astigmatic difference. Its ultrasonic autofocus motor (USM) enables fast, smooth and silent autofocus action and full-time manual focus override allows for the precision of manual focus even in One shot AF modeProduct Features: Aperture range: f/1.4-22 Lens EF mount Diagonal angle of view: 46 degreeFilter size is 58 mmFocal length is 50 mm Full frame digital sensorWeight: 290 gDiaphragm blades: 8Dimension: 7.37 x 5.08 cmMaximum reproduction ratio 1: 7.