The 17-40mm can capture massive landscape views when fitted on a full-frame body and zoomed-out.

Unsurprisingly there’s some geometric distortion, but if you’re careful with the composition it can be effectively hidden.

The crops are detailed and relatively sharp, with only the slightest coloured fringing in high contrast areas.

The crops are impressively sharp and detailed and only soften slightly in the extreme corners.

Note this shot was taken with a polarising filter, hence the darkening in the upper right corner.

Ultra wide angles aren’t just for standing back and capturing as much as possible. They’re also invaluable at close range when there’s literally no room for manoeuvre.

Here it’s allowed us to capture the entire food stall, complete with menus and ingredients on the periphery.

Considering the 5D was set to 800 ISO to cope with the low light, noise levels are quite low, and the crops are also sharp at the edges, even with the aperture wide open at f4.

The crops show a little motion blur on the llama and some distortion in the extreme corners, but the background is very detailed.

The crops are pretty sharp and detailed, and the darkening in the top right corner is due to a polarising filter.

The 17-40mm is so much fun zoomed-out that you often forget it covers a complete range of wide focal lengths.

Here we’ve zoomed-into 35mm, so are approaching its upper limit. The main shot looks fine, but there’s considerable softening in the corners. This is also apparent in our outdoor results pages compared to the 24-105mm lens.

We may have a poor copy, but from our test shots, the 17-40mm performs best in the corners at its widest focal lengths.