This lens is Canon's answer for users of its APS-C format cameras looking for a wide-angle lens. It equates to a 16-35mm in 35mm full frame format, so it provides users with an extremely wide-angle lens.
As the lens is an "EF-S" format, it will only fit crop frame cameras, which is a real shame as it's a terrific lens that full frame users would really enjoy!
Pros
- Hardly any distortion at all -- less even than Canon's pro "L" 16-35mm lens
- Extremely sharp
Cons
- Does not ship with lens hood, which is essential for cutting down on flare
- Using a built-in flash at 10mm will cast a shadow
Canon EF-S 10-22mm f3.5/4.5 USM Lens Review
This is a fantastic little lens, which I wouldn't hesitate to buy if I shot on a crop frame Canon camera. Its aperture range is a little limited compared to its biggest rival -- the Tokina AT-X 116 Pro DX lens -- but it has a far greater focal length range. I also think the Canon just edges it on the lack of distortion front.
Autofocus
USM stands for "ultra-sonic motor," which means that the lens focuses silently. Autofocus is extremely fast as well. Switching to manual focus is achieved by flicking a small switch on the side of the lens, and it provides smooth results.
Build Quality
This lens is extremely lightweight, weighing only 13.6 ounces (385 grams), and it is around 3.5 inches long. It's made from plastic, but it certainly feels very stable -- much more so than many plastic lenses. The lens mount is metal. Although it doesn't weigh much, the lens is large because of its extreme wide-angle!
Optics
The Canon 10-22mm produces excellent results throughout its range, with only a slight drop-off at extremes. Its optimum apertures are f5.6 and f8, with a slight loss of corner sharpness at wider apertures. The difference is negligible.
Remarkably for such a wide-angle lens, the Canon only shows signs of barrel distortion at its widest angle -- 10mm. Chromatic aberration is visible at 10mm and 12mm, but it is so slight that you're unlikely to notice it, unless you really zoom in to your images.
Conclusion
If you're a user of a Canon APS-C camera, this is the wide-angle lens to own. Its quality is absolutely astonishing for the price, particularly when you consider that it outperforms the manufacturer's two pro wide-angle lenses in many aspects.
The only frustration is that its not available for full frame camera users!