The Canon EF 17-40mm f/4.0L covers a range from ultra wide to almost standard focal lengths and includes most popular wide angle classics such as 20, 24, 28 and 35mm. To illustrate the range in practice we mounted an EOS 5D on a tripod and photographed the same scene with the EF 17-40mm at its shortest and longest focal lengths, then repeated the process a few moments later with the EF 24-105mm for comparison.

Below are the shots taken with each lens at their shortest focal lengths and as you’d expect, the EF 17-40mm captures a much wider field. As we’ll show in the Gallery, this allows you to capture massive views even at close range, which can be handy if you literally can’t step back any further.

Canon EF 17-40mm f/4L USM		Canon EF 24-105mm f/4L IS USM
17-40mm at 17mm, f8 (17mm equivalent)		24-105mm at 24mm, f8 (24mm equivalent)

Next up came the long-end of each lens, and again below are shots taken with the EF 17-40mm and EF 24-105mm when zoomed-in. Obviously the latter can deliver a much tighter field – indeed over two and a half times greater than the EF 17-40mm. This clearly makes the EF 24-105mm a more flexible general purpose lens, especially with its Image Stabilisation, but wide angle fanatics will still find the EF 17-40mm a surprisingly practical day-to-day lens and it also has the benefit of being cheaper.

Canon EF 17-40mm f/4L USM		Canon EF 24-105mm f/4L IS USM
17-40mm at 40mm, f8 (40mm equivalent)		24-105mm at 105mm, f8 (105mm equivalent)