Canon EF 17-40mm f/4L USM Lens

There are some lenses that you just HAVE to have in your lens kit ... this is one of them. Wide angle lenses are increasingly popular, particular with the 1.6x crop factor in the consumer-line of Canon SLRs (10D, 20D, Rebel, Rebel XT), and that has driven both the supply and demand for high-quality wide-angle lenses that are also affordable.

At about $700 USD, this is a terrific starter lens for moving into L glass. The lens is fast and sharp, with little vignetting and chromatic aberration. It can be a little bit soft at f/4, but it's fantastic outdoors. The build quality is classic L.

A natural comparison is to the Canon EF 16-35mm f/2.8 L, and the faster spec is nice. But it's widely accepted that this lens is the faster of the two, and considerably cheaper. Don't even bother comparing it against the Canon EF-S 18-55 f/3.5-5.6 USM. If you like wide angles, this one is a terrific choice -- I leave it on my camera all the time. I would only consider replacing this with the Canon EF 24-70mm f/2.8 L, but only if I move up to a full-frame sensor.

Consider complementing this lens with the Canon EF 70-200mm f/4 L (also a good deal) and the Canon EF 50mm f/1.4.