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

A lovely lens for the price, very fast to focus and very quiet. I use it on a 600D body so only use the centre area of the lens. I suffer no curving on the edges as full frame sensors are reputed to suffer. As you would expect for a "L" series lens, it's built like a tank with weather sealing.

Consistent Output; Easily Interchangeable; Quick Focus; Rugged; Sharp Focus; Strong Construction

Have just gotten my first full frame camera and wanted a wide angle lens to go with my new camera, my crop frame wide angle lens sadly would not fit my new camera. I have always shot with canon cameras and canon L lens, but had now I have moved over to a Sony mirrorless a7ii full frame camera with a...

This is a good quality product that offers good value for money in the very short term. Although as with most products of this type, the value will deteriorate over time and should be able to get a cheaper version next year. It's a great device with plenty of features that I would highly recommend.

Good Value Product

Not many

Have had lens for a few years now. At one time also had the 16-35 F/2.8, but honestly ended up using this lens more because it is so much more portable (smaller, lighter). While the new 16-35 v2 is sharper in the corners, it is double the price.

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

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.

Hey thanks guys. We are a private New Zealand newspaper group and have just bought a lens for our photographers from Smifu. Yes we were nervous and did as much checking as we could before paying. Guess what? All went well.

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

I used this lens on my 7D for about 5 years until my camera and lens were stolen. After a year of waiting and saving up, I finally made up my mind to buy this lens again. I've become very used to how the lens shoot over the years and that was the main reason that led me to purchase it again.