Conclusion: The ultra-wide group to which this lens belongs has gone a long way towards overcoming the biggest drawback of cropped sensor dSLR’s, that of lost angle of view at the wide end. Being newly designed, it has addressed all of the other problems that have been thrown up by digital sensors and optically, if they had stopped at 20mm there would be very little to pick up on.
Pros: Good optical quality, Nice size and weight, No unexpected nasties.
Cons: Price, Restricted fitting (Won’t fit D30/60 or 10D), Lens hood is an optional extra.
Excerpt: ePHOTOzine lens guru, Gary Wolstenholme shows us the Canon EF-S 10-22mm f/3.5-4.5 zoom lens. An ultra-wide angle zoom lens for use on Canon's EF-S compatible cameras, which gives an equivalent angle of view of a 16-35mm lens on 35mm cameras.
Pros: Excellent resolution in the centre at most apertures and focal lengths, Light weight, Good build quality
Cons: May be prone to flare and no lens hood is supplied, Falloff in resolution towards the edges at 22mm
Summary: Canon EF-S 10-22mm f/3.5-4.5 USM is an interesting ultra-wide zoom lens. At least for those willing to invest in an EF-S lens. The lens has some shortcomings - build quality leaves room for improvement, the lens does not come with a lens hood (surprise to me considering its price tag). The lens showed noticeable vignetting at 10mm and some softness at the borders across all focal lengths.
Conclusion: The Canon EF-S 10-22/3.5-4.5 is a very good lens. There is a little corner softness wide open at 10mm, but overall the image quality is excellent. Those who claim that this lens shows "L" quality performance may not be wrong. It is $150-$200 more than the 3rd party competitors, but it does have a wider zoom range than any of then, plus it has a silent, fast, USM ring motor with full time manual focus.
Excerpt: With framing equivalent to a 16-35mm zoom on a full frame body, the Canon EF-S 10-22mm f/3.5-4.5 USM Lens provides EF-S compatible camera body owners with the ultra-wide angle focal lengths so often missed on this small-sensor format camera.
Summary: The Canon EF-S 10-22mm equips budget to mid-range Canon DSLRs with ultra-wide angle coverage. While the equivalent coverage of 16-35mm sounds extreme, our Gallery shows the range can be surprisingly useful in practice.
For example most of us have faced landscapes, buildings, interiors or even group shots which are simply too large to squeeze into the field of view of normal lenses, or found ourselves in situations where a wall or cliff edge meant we couldn’t step back...
Pros: Extreme wide angle coverage., Low geometric distortion., Fast, quiet and internal USM focusing., Relatively small and light.
Cons: Lens hood not supplied as standard., Modest macro capabilities., Sigma 10-20mm worth considering., Incompatible with full-frame bodies.
Canon’s EF-S 10-22mm f/3.5-4.5 USM; An Ultra-Wide Zoom Digital APS-C Format Lens
1 December 2001
Excerpt: The Canon EF-S 10-22mm f/3.5-4.5 USM (16-35mm equivalent in 35mm parlance) was designed to cover the APS-C format, specifically the EOS 20D and both EOS Digital Rebels (plus future APS-C models). Canon's EF-S lenses (S = Short Back Focus) are physically matched to these cameras. This design also results in a smaller and lighter lens (3.5" long and less than 14 oz).