Canon EF 17-40mm f/4L USM lens (full-frame tests)

Canon EF 17-40mm verdict

Good points
Extreme wide angle coverage
Well-corrected at wider focal lengths
Fast and quiet USM focusing motor
An exotic but affordable ‘L’ lens

Bad points
Zoom range too limited for general purpose
Soft corners at 40mm focused at infinity
Unimpressive macro capabilities
Light fall-off at wide angle (but expected)

(relative to other zooms)


Build quality:
Optical quality:


22 / 25
22 / 25
19 / 25
20 / 25



The EF 17-40mm f/4.0L is one of the best lenses in Canon’s range. It brings you a taste of the truly exotic with ultra-wide coverage, while boasting ‘L’ quality all at a surprisingly affordable price. Sure it ain’t exactly cheap, but it’s considerably more affordable than the EF 24-105mm f/4.0L and almost half the price of the EF 16-35mm f/2.8L.

The coverage may sound extreme, but as we’ve shown in our Gallery, it can be more practical than you’d think, and if you mostly shoot at wide angle, you’re effectively getting at least four classic prime focal lengths in one convenient package. Coupled with a full-frame body like the EOS 5D, it’s a great performer.

On the downside, our samples were quite soft in the corners when zoomed-into 40mm and focused at infinity, and the combination of full-frame digital with wide angle means you’ll have to put up with quite significant light fall-off in the corners. There’s also the annoying fact many EOS 5D owners wanting a practical two lens kit could end up with a gap between 40mm and 70mm. If you’re after a more practical general purpose lens, check out our EF 24-105mm review.

But you only have to look at the shots in the Gallery to see the unique opportunities open to the EF 17-40mm. It’s a truly exciting lens to use in practice with a full-frame body and a valuable addition to any lens collection. The EF 16-35mm may seem more exotic still with its slightly wider coverage and impressive f2.8 aperture, but the EF 17-40mm is bright enough for most situations and the slightly longer coverage makes it more practical and a lens you could arguably leave on the body for general use – and crucially you’re getting ultra-wide coverage and ‘L’ quality at a relatively low price.

So the Canon EF 17-40mm f/4.0L comes Highly Recommended both for full-frame body owners, along with those who have APS-C bodies and are thinking of upgrading to full-frame in the future – see our 400D lens upgrade group test. It may not be as flexible as the EF 24-105mm, but it’s much more exciting and cheaper too. Put it this way, if you’re into wide angle photography with a full-frame body and don’t already have the EF 16-35mm, we’d say it’s a mandatory purchase.

For an overview of the headline features of this lens, check our Canon EF-S 17-40mm lens video tour.

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