Summary: Out Standing Lens! The Filters are Great, How ever The lens Holder fell apart the First Time I used it! And just to let you know, although I assumed that for a High end L- Lens that it had a Image Stabilizer: IT DOES NOT! Still great photos and very easy to use.
Excerpt: The 17-40L is often noted for having soft edges/corners at wider apertures, and this is true. However, stop the lens down and performance is stellar.<br /><br />Color and contrast are incredible. I have used the 16-35 II, 14L II and third part options as well... The 17-40L remains my favorite.<br /><br />The 16-35 II offers nothing except for the f/2.8 over the 17-40 at double the cost.
Pros: Consistent Output, Durable, Fast / accurate auto-focus, Lightweight, Rugged
Excerpt: I needed a wider lens than my 24-70 for various situations (landscape, architecture etc...) so I purchased this 17-40 f/4. It is a compact, light, half the price of the faster 16-35 and an overall great lens. I was surprised how much I enjoyed using it right from the start. It was essential for capturing the beautiful landscape in Iceland. I do not have any complaints about this lens at the moment.
Pros: Easily Interchangeable, Fast / accurate auto-focus, Lightweight
Excerpt: I already have the 10-22mm lens, so I got this to be more of a standard zoom for my 7D, and it does an amazing job. While the F/4 can be a bit limiting, it's more than adequate for most of the shooting I do. The only complaint I can think of is that the included lens hood is intended use on a full frame camera. I purchased the Canon Ew-83J lens hood to use, and it works like a charm.
Pros: Consistent Output, Durable, Fast / accurate auto-focus
Excerpt: I mostly take landscape photos and it was really up in the wire about the 17-40 or the 16-35 lens. I did a lot of research and after my finding I just could not see the benefit of going with the 16-35 for the kind of photography I do. That being said this lens is an amazing addition to my bag. Very sharp and wide photos, and the lens itself is not to heavy for those long hikes. I'm sure I'll get many years of use out of this 17-40 lens.
Pros: Durable, Easily Interchangeable, Lightweight, Strong Construction
Excerpt: This lens is a great budget alternative to Canon's 16-35mm, basically half the price. I'm not much of a wide-angle shooter, but when I need it, I'm glad to have this in my bag. I mainly use it for shooting architectural, so the relatively slow f/4 doesn't bother me.