Sigma 17-70mm F2.8-4 Contemporary
Vignetting
Vignetting, or darkening of corners, occurs due to imperfect coverage of the whole area of the sensor. In order to test the vignetting of the 17-70mm, we took a series of photos of the sky at varying apertures and focal lengths.
Click on any photo to enlarge it in a scrollable lightbox.
Stopped | 17mm | 50mm |
| Wide-open |  |  |
| 1 stop |  |  |
| 2 stops |  |  |
| 3 stops |  |  |
| 4 stops |  |  |
| 5 stops |  |  |
70mm | ||
| Wide-open | | |
| 1 stop |  | |
| 2 stops |  | |
| 3 stops |  | |
| 4 stops |  |
Verdict
Generally speaking, there is some vignetting wide-open at all apertures and all focal lengths. The vignetting becomes negligible when the lens is stopped down by one stop, and it not discernible when stopping down by two or more stops. These results are respectable and they're exactly what we expected to see in a premium walkaround lens.
Based on the test photos above, we observe that the vignetting worsens slightly at longer focal lengths. Conversely, the least vignetting occurs at 17mm. This means that in real-life landscape photos shot at wide focal lengths will virtually never have any dark corners.
