The 17-40 is an affordable and well-known ‘L’ series lens. Designed to be an ultra-wide angle lens for full frame cameras, however it’s quite versatile: its handy zoom range ends at 40mm, and zooms out to an ultra-wide angle of 17mm. You get quite a huge angle of view at 17mm when you’re using a full-frame camera, and the lens’s constant maximum aperture of f/4 means it lets in a reasonable amount of light.
If you own one of Canon’s less expensive APS-C cameras, then 17-40mm is quite a good general purpose zoom range, although it’s a bit of an old fashioned idea to use it in this way. The lens really was born to be on a full frame camera, for its super-wide angles.
The Canon 17-40mm f/4 USM ‘L’ is a very nicely made lens, which is quite good value, so it’s no wonder it’s always been quite popular. There’s no denying that it has some quite noticeable optical deficiencies, such as soft corners and problems with distortion. But despite this, the lens tends to give very good-looking pictures, with dramatic colours and contrast, and its impressive zoom range makes it useful and fun to use. If you’re on the market for a full-frame, ultra-wide angle lens, then this Canon lens is an enjoyable and good value option.
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