Sigma 17-70mm f/2.8-4 DC Macro OS HSM C (Nikon) review: update to popular standard zoom lensBy Kevin Carter - Friday June 21 2013 Lens Review
With a DxOmark score of 16 points on the 16 Mpix Nikon D7000, the new Sigma performs well for this type of lens. Sharpness is improved over the previous iteration by 1P-Mpix. In fact, 7P-Mpix is the average sharpness score for a lens like this, and was the score achieved by the previous iteration. However, the improvements in sharpness are mainly in the centre of the frame and at the expense of the outer field. Scores for Transmission, Vignetting, Distortion and Chromatic Aberration are all respectable for a lens like this.