The Canon EF 17-40mm f/4L USM ($839.99 direct) is an ultra-wide to normal zoom lens that is compatible with Canon EOS SLR cameras. When used on a full-frame body, the lens provides an extremely wide 17mm field of view on the wide end with a 2.4x zoom factor that takes it to a normal 40mm field of...

The Canon EF 17-40mm f/4L USM ($839.99 direct) is an ultra-wide to normal zoom lens that is compatible with Canon EOS SLR cameras . When used on a full-frame body, the lens provides an extremely wide 17mm field of view on the wide end with a 2.4x zoom factor that takes it to a normal 40mm field of...

Ultra-wide field of view; Reasonable price tag; Good center sharpness

Muddy edges and corners at 17mm; Some distortion; Noticeable color fringing

The Canon EF 17-40mm f/4L USM lens is an inexpensive alternative to the 16-35mm f/2.8, but its edges are muddy at its widest angle. (3 out of 5) Pros Ultra-wide field of view Reasonable price tag Good center sharpness Cons Muddy edges and corners at 17mm Some distortion Noticeable color fringing The...

Ultra-wide field of view; Reasonable price tag; Good center sharpness

Muddy edges and corners at 17mm; Some distortion; Noticeable color fringing

The Canon EF 17-40mm f/4L USM ($839.99 direct) is an ultra-wide to normal zoom lens that is compatible with Canon EOS SLR cameras. When used on a full-frame body, the lens provides an extremely wide 17mm field of view on the wide end with a 2.4x zoom factor that takes it to a normal 40mm field of view at the long end. It features a constant f/4 aperture and a silent focusing motor. The lens is a part of Canon's top-end L series of lenses—which are easily identified by the red band around the front element. It isn't as sharp as the Canon EF 16-35mm f/2.8L II USM($1,745.00 at Amazon), and is prone to showing color fringing around highlight edges. But if you're looking for an ultra-wide zoom and you're on a budget, some work in Lightroom can make up for its shortcomings. The lens is short and squat at 3.8 by 3.3 inches (HD). It weighs about 1.1 pounds, and uses rather large 77mm filters. The lens can focus as close as 10.8 inches, regardless of the focal length. There's a large man...

The Canon EF 17-40mm f/4L USM lens is an inexpensive alternative to the 16-35mm f/2.8, but its edges are muddy at its widest angle.

Ultra-wide field of view; Reasonable price tag; Good center sharpness

Muddy edges and corners at 17mm; Some distortion; Noticeable color fringing

Canon understands the underlying inimitability of each photographers creative vision, and thus proffers an exclusive camera lens to vivify their imagination. Each piece from the excellent array of Canon lenses is truly reflective of the signature know-how and craftsmanship associated with Canon.

Very sharp, found it to be much sharper and more accurate than my 24-70 2.8L, however when open wide at 17mm, there is some considerable distortion to watch out for especially with portraits. Photoshop's lens corrector tool should be able to help with that though.

Great for landscapes, sunrises, and sunsets - particularly in combination with graduated neutral density filters to balance exposure of land and sky. Amazing for indoor room photos - a must for any Realtor. Superior for architects' pictures of structures.

Easily Interchangeable; Fast / accurate auto-focus; Lightweight

Pros: Lightweight, Fast / accurate auto-focus, Easily Interchangeable Cons: Other thoughts: Great for landscapes, sunrises, and sunsets - particularly in combination with graduated neutral density filters to balance exposure of land and sky. Amazing for indoor room photos - a must for any Realtor.

I loved he price I got this lens for and the quality is very nice, I am happy to have got it from homeshop and the lens can focus to a very close object also.

a good lens at a bargain price, but if you want the best IQ you need zeiss prime lenses

cheap; light and good image quality

corners can be really bad at f4