Some sample shots from Canon 10-22mm and Sigma 10-20mm with 100% crop have just been posted by Dougal in Canada.
Here’s what Dougal says about his test:
“My test limits the Canon to 20mm and F-stops identical to those of the Sigma. For simplicity I’ll only provide wide open (obviously the Canon is stepped down a little) results.
I used two scenes for each of the two focal lengths. Draw what ever conclusions you wish…
All images were processed in CaptureOne with no sharpening and Identical exposure and white balance settings. ISO setting for all shots was ISO100, F4 (10mm) shots were shot at 1/800s and F5.6 (20mm) shots at 1/400s. A cable release was also use to operate the shutter.”