Canon EF 17-40mm f/4L USM tested with Canon EOS 400D full review Cameralabs corner sharpness results

More results : Outdoor / Resolution / Corner sharpness / Fringe and macro / Geometry / Vignetting

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Canon EF 17-40mm f/4L USM corner sharpness using Canon EOS 400D / XTi

To measure and compare the corner sharpness of each lens using the Canon EOS 400D, we photographed the Enhanced Digital Camera Resolution Chart with each lens at its shortest and longest focal lengths using various aperture settings. The 400D was set to Large Fine JPEG mode and its Standard Picture Style. All four lenses were tested within moments of each other under identical lighting conditions.

The crops are taken from the lower left corner of the chart and presented here at 100%. The wide angle crops show a slightly larger area of the chart because the minimum focusing distances forced us to shoot from a little further away. No crops have been resized.

Zoomed-out to wide angle, the EF 17-40mm performs well in the corners, although it should do being corrected for a much larger full-frame body; that said, it's far from perfect on a cropped body and here exhibits a little coloured fringing and a drop in contrast at smaller apertures.

Zoomed-into its longest focal length and with the aperture wide open, the EF 17-40mm is actually quite soft in the corners - this is a bit of a disappointment considering again it should be corrected for a much larger full-frame body. That said we found this lens performs much better when zoomed-out than it does zoomed-in, and as the results below show, the corner sharpness can be greatly improved by closing the aperture a little.

Canon EF 17-40mm f/4.0L USM	Canon EF-S 17-85mm f/4-5.6 IS USM	Canon EF-S 18-55mm f/3.5-5.6	Canon EF-S 17-55mm f/2.8 IS USM

f2.8 not available	f2.8 not available	f2.8 not available	17-55mm EF-S at 17mm f2.8


17-40mm EF L at 17mm f4	17-85mm EF-S at 17mm f4	18-55mm EF-S at 18mm f3.5	17-55mm EF-S at 17mm f4


17-40mm EF L at 17mm f8	17-85mm EF-S at 17mm f8	18-55mm EF-S at 18mm f8	17-55mm EF-S at 17mm f8


17-40mm EF L at 17mm f16	17-85mm EF-S at 17mm f16	18-55mm EF-S at 18mm at f16	17-55mm EF-S at 17mm f16

Canon EF 17-40mm f/4.0L USM	Canon EF-S 17-85mm f/4-5.6 IS USM	Canon EF-S 18-55mm f/3.5-5.6	Canon EF-S 17-55mm f/2.8 IS USM

f2.8 not available	f2.8 not available	f2.8 not available	17-55mm EF-S at 55mm f2.8


17-40mm EF L at 40mm f4	17-85mm EF-S at 85mm f5.6	18-55mm EF-S at 55mm f5-6	17-55mm EF-S at 55mm f5.6


17-40mm EF L at 40mm f8	17-85mm EF-S at 85mm f8	18-55mm EF-S at 55mm f8	17-55mm EF-S at 55mm f8


17-40mm EF L at 40mm f16	17-85mm EF-S at 85mm f16	18-55mm EF-S at 55mm f16	17-55mm EF-S at 55mm f16