Sigma 10-20mm F3.5 vs F4.0-5.6

Image Quality: Vignetting

Vignetting, by definition is a reduction of an image’s brightness compared to the image center. Ultra-wide lens are more susceptible to optical vignetting because they cover a wider field of view.

For this vignetting test, we took a series of pictures of a grey board and looked for an even spread of grey across the image. All lenses have some vignetting but it usually falls within acceptable tolerances. For the Sigma lens, in this review, we were looking for an even spread of grey across the image. The other factor that effects the lens vignetting is the F stop. As the lens is stopped down it will reduce the effects of the optical vignetting. In reviewing the images, keep in mind that some may be darker than others, but that does not necessarily indicate a problem. Problems exist when one or more of the corners are significantly darker than the center.

Vignetting Image Test

Conclusion

Both the lenses did very well on the vignetting test. Both Sigma lenses had some minor vignetting in the corners at 10mm and 14mm respectively, when they were wide open. Both lens improved dramatically when they were either stopped down or moved beyond the extreme range of the zoom. Both lenses were so similar in the vignetting, that it is difficult to tell them apart.


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