Canon EF 17-40mm f/4L USM Ultra Wide Angle Zoom Lens for Canon SLR Cameras: Customer Reviews & Product Details

Despite this lens is not good for full frame cameras, it is an excellent option for a APS-C size sensor such as Canon 50D and Rebel T1i. On a full frame camera, this lens produce soft corners however, because of the crop effect of APS-C sensor this problem does not show up in the pictures and the lens deliver Pin Sharp pictures from the center to the corner always. As any Canon L series lens, the image is superb with high resolution and wonderful color saturation. The construction is also superb and comes with lens hood as well which is a plus. One also have to consider the prices which is very low for a Canon L lens. I certainly recommend this lens for any APS-C sensor cameras. It is a must have... A keeper... A winner...

I have these lens for less than a month now and whenever I go out I want to take great pictures, I make sure I have this lens on my camera I wont even think of using other lens like the other day I was completely disappointed with the pictures, now I have to redo the shot again, you can check the pictures I upload and rate it the best you can. This L lens made me look good and professional try to have it if you can afford it its worth the time your out there shooting when you upload and check your picture you wont be dissapointed

My wife uses this lens and I take it when I'm traveling on my 5D. It is a fast and sharp lens that I love to use for landscapes, group pictures, and travel photography.

Here's the basics:
1. The price is unbeatable for an L-class lens.
2. Reliable -- it's been rained on and traveled 100,000 miles. No issues.
3. Its sharp and even sharper on a Canon 5D with no crop ratios.

Please understand this is not for low light (unless you spike your ISO up).

I have the 5Dm2 and this is my first L-series lens (I couldn't afford the 24-105 when I bought the body), and boy is it great!

I love the realistic skin tones, high contrast, and amazing color. The wide angle is perfect to get 3 walls in small room shots. I took some shots for a flower arrangement designer of some banquet rooms she did and they came out super sharp and got everything!

At 17mm this lens does give a bit of distortion in the corners, but it's only noticeable if you're close to a wall, low low ceilings, etc.

I am very impressed with this lens. Unbeatable for the price!

This lens does a fine job, but I did notice that when I took picures of builings with words or other features that had good straight-lined contrast, the sharpness was exceptional. However, when I take pictures of nature scenes, it seems that trees, rock formations, etc. look a little soft. Not sure if this is the camera or the lens. I do wish I had a full sensor camera for this particular lens, maybe sometime in the far future.