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Lens review

2010-05-25
 

Sigma 8-16 mm f/4.5-5.6 DC HSM

6. Distortion

Already in the case of its first 10-20 mm model Sigma showed that it can correct the distortion in its ultra wide angle devices. We were even more curious how the 8-16 mm model would fare in this category.

In this case at 8 mm, where we deal with 119.1 degrees angle of view, we noted down the barrel distortion of –2.59%. Such value is hardly imperceptible but, taking into account the parameters of the tested lens, it is rather acceptable. It would be difficult to present an unambiguous assessment here as you can hardly find any other device for comparison.

With the increase of the focal lengths the problems with the bending of straight lines decrease. In the middle of the range the distortion is still barrel but its value becomes negligible and amounts to just –0.36%. At the maximum focal length we already have 1.1% “pincushion”

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One more thing is worth mentioning here. The measured and analyzed distortion concerns the bending of straight lines and it constitutes just one element. The second one is deformation in the frame corners, which, in such a wide angle lens with a rectilinear mapping (so trying to render straight lines as straight), is impossible to avoid. It will be much less bothersome in a “fisheye” type of lens but in that case we simply must forget about any straight lines.


Canon 50D, 8 mm
Sigma 8-16 mm f/4.5-5.6 DC HSM - Distortion
Canon 50D, 12 mm
Sigma 8-16 mm f/4.5-5.6 DC HSM - Distortion
Canon 50D, 16 mm
Sigma 8-16 mm f/4.5-5.6 DC HSM - Distortion

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