STM functionality provides quiet, smooth and continuous autofocus during video operation (video continuous autofocus only when used with the Canon EOS Rebel T4i). The circular aperture formed by 7 diaphragm blades combined with the wide aperture can give you beautiful bokeh--the out-of-focus background areas of your images. This 40mm lens will give you a view equivalent to 64mm when used on a camera with an APS-C sensor, and is able to focus as close as 11.81". If you're looking for a "normal", everyday lens, this is a good place to start.
Continuous Autofocus for Video With T4i
Bright f/2.8 Aperture
Lightweight 4.6 oz Lens
64mm Equivalent If Used on APS-C Camera
Aspherical Element--High Image Quality