Не стоит торопиться с выводами, во-первых, на 200мм картинка заметно отличается http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=404&Camera=453&Sample=0&FLI=4&API=0&LensComp=469&CameraComp=453&SampleComp=0&FLIComp=4&APIComp=2
во-вторых, имеет смысл почитать комментарий тестера :
"I got further with my second Sigma 70-200mm f/2.8 EX DG HSM II Macro Lens (it passed physical inspection). But, I quickly determined during the ISO 12233 resolution chart test that this lens had a severe front-focus problem. The ISO 12233 chart results are posted for this lens (sample 2) - please note that the 70mm and 85mm samples from this lens were framed using AF. The front-focusing was so bad that proper manual focusing from the same shooting position caused the image to be noticeably reduced in the frame when accurately manual-focused - making the chart details slightly smaller than they should be. Do not use samples from these two focal lengths from this lens sample for distortion comparisons (use lens sample 1 which is the default).
I was very disappointed to yet receive another front-focusing copy of the Sigma 70-200mm f/2.8 EX DG HSM II Macro Lens on my third attempt. Two of these lenses came from B&H and a third came from Amazon.com (just to mix things up). I tested these lenses on two Canon EOS 1Ds Mark III bodies (one is Canon-calibrated) and a Canon EOS 40D body. All delivered the same AF results - consistently front-focusing.
I don't plan to try a fourth copy.
The quality problems I experienced are especially disappointing because this lens has the potential to be a good one. "
Вот так