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Canon EF-S 17-85mm geometry, wide angle
To measure geometric distortion we photographed a custom test chart consisting
of a grid pattern with perfectly straight lines. The lenses were tested
at their widest focal length with an aperture of f8 using a Canon EOS-350D
/ Digital Rebel XT in Aperture Priority mode. The images were analysed with
Imatest using 5th Order line calculation and the full areas presented here
at a reduced resolution.
The 17-85mm EF-S exhibits greater barrel distortion than its rivals at their
widest focal length, including the budget 18-55mm EF-S model. The 17-40mm
EF L performed best in this test. |
Canon EF-S 17-85mm f4~5.6 IS USM |
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Canon EF-S 18-55mm f3.5~5.6
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Canon EF 17-40mm f4.0L USM
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17-85mm EF-S at 17mm f8
Distortion: 5.71% barrel |
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18-55mm EF-S at 18mm f8
Distortion: 3.35% barrel |
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17-40mm EF L at 17mm f8
Distortion: 2.9% barrel |
Canon EF-S 17-85mm geometry, telephoto
To measure geometric distortion we photographed a custom test chart consisting
of a grid pattern with perfectly straight lines. The lenses were tested
at their longest focal length with an aperture of f8 using a Canon EOS-350D
/ Digital Rebel XT in Aperture Priority mode. The images were analysed with
Imatest using 5th Order line calculation and the full areas presented here
at a reduced resolution.
The 17-85mm EF-S exhibits greater pincushion distortion than its rivals
at their longest focal length, including the budget 18-55mm EF-S model.
Again the 17-40mm EF L turned out the least distorted result. |
Canon EF-S 17-85mm f4~5.6 IS USM |
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Canon EF-S 18-55mm f3.5~5.6 |
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Canon EF 17-40mm f4.0L USM |
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17-85mm EF-S at 85mm f8
Distortion: 0.967% pincushion |
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18-55mm EF-S at 55mm f8
Distortion: 0.389% pincushion |
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17-40mm EF L at 40mm f8
Distortion: 0.187% pincushion |
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