Sigma 70-300mm DG OS: a low-cost telephoto zoom put to the test

Mounted on a high-resolution full-frame camera, the Canon EOS 1Ds Mark III, this lens offers a pretty good resolution of 50 lp/mm. At such a focal length, distortion is never really a problem, so it is not surprising that its distortion score is very low.The DxOMark score map also tells us that this lens achieves an acceptable level of quality under low-light conditions up until 200mm at f/5.6. Overall, however, its quite low DxOMark score of 12 shows that this lens is not a great performer even when mounted on the excellent Canon 1Ds Mark III.The measurements