The Canon EF-S 10–22mm f/3.5–4.5 USM is an ultra wide-angle zoom lens designed for all EF-S mount digital EOS cameras.  Equivalent to a 16-35mm zoom, it offers excellent performance and optics uniquely engineered for digital SLR use.  This advanced lens lets you get extremely close to subjects, exaggerating the difference in size between a near object and its background.  An Ultrasonic Motor (USM) provides fast, smooth and quiet autofocus action and manual focus override in the One Shot AF mode enables precise focusing at all times.  An Ultrasonic Motor (USM) provides fast, smooth and quiet autofocus action and manual focus override in the One Shot AF mode enables precise focusing at all times.

ULTRA SONIC MOTOR (USM)  
Canon's USM lenses employ a motor powered by ultrasonic waves that produce a quiet, yet high-speed AutoFocus. You can enjoy high performance with low noise in a variety of shooting situations.    

Ultra Low Dispersion (UD)
Glass Canon's Low Dispersion technology is engineered to reduce chromatic aberrations, eliminating the tendency of light of different colors to focus to different points at the image plane.  This means your images will come out crisp and clear, with less of a chance of defracting light into an unwanted rainbow of colors.  Take shots exactly like you want, without any flare-up or blurring.

ASPHERICAL DESIGN
Canon's aspherical lens design creates a more complex surface profile.  This helps to greatly reduce spherical and other optical aberrations.  The design further ensures consistent imaging performance throughout the entire focal range, while delivering incredible sharpness up to the periphery of the image. 

ANTI-REFLECTIVE COATING
The Canon anti-reflective coating is an optical design feature which ensures superior clarity and image brilliance, even in poor or unfavorable lighting conditions.  Canon applies the anti-reflective coating through a special process, layering the lens surface in order to substantially reduce unwanted flare or ghosting.  This process helps to ensure incredibly rich image contrast and true color fidelity. 

MANUAL FOCUS
Manual focusing means you have all the control at the end of your fingers.  Canon lenses feature a specially designed ergonomic construction that is noticeable at first touch.  The large rotation angle of this lens guarantees precise focusing.  The mechanism moves super smoothly and without extra play, furthering the intuitive interaction along the focal plane. 

ADVANCED APERTURE DESIGN
With Canon lenses you can create stunning Bokeh effects, thanks to the finely tuned features and advanced optical design.  By keeping the background intentionally blurred, additional focus is created on the subject of an image.  The uniquely engineered diaphragm blades of this lens, along with the virtually circular aperture, deliver stunning renditions of highlights the back and foreground.