Canon EOS 400D / Digital Rebel XTi lens upgrade group test Cameralabs geometry results

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

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Canon EOS 400D / Digital Rebel XTi lens upgrade wide-angle geometry

To measure and compare wide angle geometric distortion, we photographed a test chart consisting of a grid pattern with each lens set to its shortest focal length and an aperture of f8. The images were then analysed with Imatest using 5th Order line calculation and the full areas presented here at a reduced resolution.

The lowest geometric distortion at wide angle unsurprisingly comes from the EF 17-40mm, because it's corrected for a full-frame body. It's impressive then that the EF-S 17-55mm scores essentially the same result here. The budget EF-S 18-55mm kit lens comes next, but falling behind with the worst result here is the EF-S 17-85mm, which exhibits quite noticeable geometric distortion when zoomed-out.

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

17-55mm EF-S at 17mm f8 Distortion: 2.87% barrel	17-85mm EF-S at 17mm f8 Distortion: 5.71% barrel	18-55mm EF-S at 18mm f8 Distortion: 3.35% barrel	17-40mm EF L at 17mm f8 Distortion: 2.9% barrel

Canon EOS 400D / Digital Rebel XTi lens upgrade telephoto geometry

To measure and compare telephoto geometric distortion, we photographed a test chart consisting of a grid pattern with each lens set to its longest focal length and an aperture of f8. The images were then analysed with Imatest using 5th Order line calculation and the full areas presented here at a reduced resolution.

The best result again comes from the EF 17-40mm, which again is expected because it's corrected for a more demanding full-frame body. Interestingly the budget kit lens comes second here, exhibiting noticeably lower geometric distortion when zoomed-in than the other two EF-S lenses.

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

17-55mm EF-S at 55mm f8 Distortion: 1.09% pincushion	17-85mm EF-S at 85mm f8 Distortion: 0.967% pincushion	18-55mm EF-S at 55mm f8 Distortion: 0.389% pincushion	17-40mm EF L at 40mm f8 Distortion: 0.187% pincushion

Canon EOS 400D / Rebel XTi lens upgrade results continued...

Outdoor / Resolution / Corner sharpness / Fringe and macro / Geometry / Vignetting

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