The Canon 50mm 1.4 USM lens is the quintessential fast 50 prime lens from Canon. It's compact, lightweight, sharp, easy to see through and focuses quickly. A great compliment to zooms especially when bag space is at a premium, it provides a rewarding shooting experience with minimum encumbrance.
The maximum aperture of f/1.4 allows for excellent background blur. Even when shooting at other apertures, the bright 1.4 aperture allows more light through to camera autofocus sensors than a zoom lens, especially valuable in poor light conditions where dimmer lenses will struggle to focus. A Canon USM Ultrasonic Motor with full time manual focus override option ensures that focus changes are implemented rapidly.