Excellent quality lens even with a full frame. I bought this to complement my 35mm F1.4L and my Carl Zeiss 18mm F3.5 Distagon. My 5D mark 3 can correct the aberrations of that lens. If you don't need 2.8 this is the only zoom choice. L quality with not much weight.

I bought this lens for my crop sensor 50D, as i wanted a 'semi-wide' angle lens for landscapes and general photography. The build quality is typical L-series (i.e. fantastic) and the lens balances well on the 50D's body.

I query some of these reviews because they are not accurate. Lets look at the 17-40 l. I shot a wedding using this lens ona full frame 5D MK2. when i viewed the results on my computer all the group shots were so bad at The 17mm they were unuseable distortion was horrific.

non beware review strapped to an apc sensor

very high distortion at 17mm end overpriced and heavy

This is a handsdown highly recommended lens if you guys are looking for upgrade. I am using Canon 60D cropped lens, I was deciding in either getting the 15-85mm standard lens or the Canon L 14-70mm "L" Lens.

CANON "L" MEANS LUXURY BUT AFFORDABLE PRICE

NOTHING

This lens auto-focuses very quickly, the build quality is superb and when stopped down, the images are very sharp. Highly recommended!

I recently switched from Nikon to Canon and this was my first lens purchased for my 5D Mark II. My decision was made after reading several reviews from websites and blogs. I have to tell you they are all right! This lens takes sharp and vibrant pictures. Good bokeh too, though not the best.

I recently switched from Nikon to Canon and this was my first lens purchased for my 5D Mark II. My decision was made after reading several reviews from websites and blogs. I have to tell you they are all right! This lens takes sharp and vibrant pictures. Good bokeh too, though not the best.

I am very satisfied with the quality of all of my Canon "L" lenses, the EF 17-40mm F/4.0 is no exception. I was looking for a wide angle zoom and thought I would rather have the F/2.8 but the price was a factor so I decided to go withe the slower F4.0.

I'm still learning how to use it, but thus far this lens way out does the lens that comes with the body. High quality pictures with exceptional captures.

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