Canon EF 17-40mm f/4L USM wide-angle geometry using Canon EOS 5D
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To measure geometric distortion we photographed a chart consisting of
a grid pattern with perfectly straight lines. The lenses were tested at
their widest focal lengths with an aperture of f8 using a Canon EOS-5D 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.
We expect to find barrel distortion increasing with wider angles, so weren't
surprised to measure the 17-40mm at 17mm exhibiting the greatest distortion here: 6.39%, although the 24-105mm isn't far behind. The
big surprise here though is the result from the 24-70mm. It
exhibits significantly lower barrel distortion at wide angle than the 24-105mm
at its widest setting. |
Canon EF 17-40mm f/4.0L USM |
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Canon EF 24-105mm f/4L IS USM |
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Canon EF 24-70mm f/2.8L USM |
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17-40mm at 17mm f8
Distortion: 6.39% barrel |
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24-105mm at 24mm f8
Distortion: 5.29% barrel |
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24-70mm at 24mm f8
Distortion: 1.86% barrel |
Canon EF 17-40mm f/4L USM telephoto geometry using Canon EOS 5D
To measure geometric distortion we photographed a chart consisting of
a grid pattern with perfectly straight lines. The lenses were tested at
their longest focal lengths with an aperture of f8 using a Canon EOS-5D
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.
Zoomed-in to their longest focal lengths, the 24-105mm and 24-70mm share
similar levels of pincushion distortion. The impressive result here comes
from the 17-40mm though, which at 40mm exhibits very little geometric distortion
what-so-ever. |
Canon EF 17-40mm f/4.0L USM |
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Canon EF 24-105mm f/4L IS USM |
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Canon EF 24-70mm f/2.8L USM |
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17-40mm at 40mm f8
Distortion: 0.44% pincushion |
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24-105mm at 105mm f8
Distortion: 1.62% pincushion |
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24-70mm at 70mm f8
Distortion: 1.82% pincushion |
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