Canon's 10-22mm is a 2.2x zoom, offering potential great value for money. The Canon EF-S 10-22mm f/3.5-4.5 USM lens review sees just how good it is in the real world...
Automatic focusing is carried out internally and benefits from Canon’s quick, quiet and reliable Ultra-Sonic Motor (USM) drive system: manual intervention is possible in AF mode if so desired. The manual-focusing ring is located between the forward-mounted zoom ring and the rearward distance window. This would be a very inconvenient position if the manual-focusing ring rotated and needed to be left unobstructed in AF mode, but that is not the case. As a result, the layout works very well and the zoom ring is particularly easy to locate even when wearing a glove.
As well as extending the zoom range Canon has also provided a slightly wider-than-usual maximum aperture of f/3.5 rather than the more common f/4. This may, however, be more of a theoretical benefit than a real one since side-by-side comparisons with an f/4 lens on another body suggest that there is no visible difference in viewing brightness. In addition, the Canon’s maximum aperture drops to f/4.5 at its 22mm focal-length setting so its advantage is not sustained.
Curiously, Canon’s lens seems to have a significantly better MTF performance at its minimum focal length than at either of the other settings tested. Peak resolution was comfortably above 0.3 cycles-per-pixel in this case and the figures remained above 0.25 cycles-per-pixel down to f/16 (except at f/3.5) for all focal lengths.
Overall, the f/3.5 maximum aperture is probably not worth having, but given that the lens is so competitively priced there is no point in turning down this additional feature. It is also worth noting that chromatic aberrations, although visible in test-chart images, were particularly low in real-world images captured using this lens.