77 of 79 people found the following review helpful
Super landscape lens for full-size sensor,
This review is from: Canon EF 17-40 mm f/4.0 L USM Lens (Accessory)
I cannot recommend this lens enough... for wide angle landscape and travel photography this lens is superb. I have used this lens for several years on a Canon 5D and previously a Canon 300D and Canon 300 film and have always found the results to be superb. For cropped sensor cameras this is going to be circa 28-70mm so pretty good as a general purpose lens and perhaps good for portrait photography.
It sits within Canon's f4 series of L series lens (and is thus half the price of its big brother 16-35 L lens)... for me given that it is most likely you will be using this lens for landscapes and thus want lots of depth of field I'm not sure the f2.8 premium is justified (even for portraits unless you are a serious professional f4 should be fine). The colour saturation seems that much deeper with this lens than the equivalent consumer lens (eg. 28-135), the build is solid (as would be expected of an L series lens) yet being wide angle and containing less glass this is not that much more expensive than Canon's prosumer range of lenses (eg. the 28-135).
For wildlife photography I find this to be a particularly complimentary lens to the big zoom lens (eg. a Sigma 50-500) so you only need to travel with two lenses. The weight is not too bad (it's the lightest L series lens) and the focussing is fast. There is no image stabiliser but at this focal length that's not an issue. Only thing to be wary of is putting filter systems on the front of the lens... it's 77mm at the front so be careful with eg. Cokin P filter systems as you may get vignetting on a full size sensor camera (not an issue for the cropped sensors as far as I know).