Lens review

Sigma 18-200 mm f/3.5-6.3 DC OS

6. Distortion

Although the distortion at 18 mm is very distinct we must admit that the Sigma compared to competitors fares well here. For example a Sony 18-200 mm had a result of- 5.5%, a Tamron 18-200 mm - 5.1%, and a Nikkor -5.4%. Against such a background the result of the Sigma, amounting to - 4.4%, we should consider to be decent.

With the increase of the focal length the distortion decreases very quickly. At 28 mm it amounts to only –0.36%, it reaches zero soon afterwards, changes the sign and increases steeply to come to 1.2% at 50 mm. Then this aberration’s level stabilizes at 1.0% within the margin of error. Once again the Sigma performs slightly better than the rivals, which, at the 50-200 mm focal length range, had the distortion in the range of 1.2-2.0%.

To sum up a visible distortion for a 11X class megazoom is something unavoidable. The Sigma 18-200 mm OS simply couldn’t have had a low level of this aberration. It wins this skirmish though, having the results better than those of its competitors.