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Lens review

Sigma C 17-70 mm f/2.8-4.0 DC Macro OS HSM

13 March 2013
Szymon Starczewski

8. Vignetting

Below you can find some thumbnails, presenting the vignetting for particular focal lengths at the maximum relative aperture and after stopping down the aperture a bit.

Sigma C 17-70 mm f/2.8-4.0 DC Macro OS HSM - Vignetting


The most problems with the light fall-off in the frame corners you can experience at the shortest focal length – there, at the maximum relative aperture, you must take into account the vignetting of 33% (-1.15 EV). Within the margin of error, it is the same result as in the case of the predecessor. If you stop down to f/4.0 you can make this aberration decrease to a moderate level of 21% (-0.68 EV). Unfortunately on further stopping down the improvement is slight – by f/5.6 the vignetting amounts to 17% (-0.54 EV) and it stays on that level by higher apertures as well.

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In the case of 28 mm focal length the maximum relative aperture is f/3.5 and there you have 26% of brightness loss in the corners (-0.88 EV). A very slight stopping down to f/4.0 decreases that aberration to 17% (-0.54 EV). By f/5.6 and f/8.0 the vignetting remains practically the same, reaching 13% (-0.41 EV). At 50 mm focal length and f/4.0 aperture it is 26% (-0.89 EV). Applying f/5.6 aperture makes this aberration disappear completely (10%). When you pass to the maximum focal length almost nothing changes. At the maximum relative aperture the vignetting is 27% (-0.90 EV) and on stopping down to f/5.6 it decreases to 10% (-0.30 EV).

The results the tested lens got in this category we assess very positively. Its dimensions, compared to the predecessor, decreased but the vignetting level remained almost the same. The new lens is currently physically as big as the first version of the Sigma 17-70 mm which, after all, had a higher vignetting level (reaching almost 40%).


Sigma C 17-70 mm f/2.8-4.0 DC Macro OS HSM - Vignetting

Sigma C 17-70 mm f/2.8-4.0 DC Macro OS HSM - Vignetting