Ok, sample time:
CLICK HERE for Full sized photos and "smugloupe" tool that allows you to zoom in to 100%
. You can download the original files as well. They are screenshot comparisons mostly at 100% in Photoshop between the Sigma 12-24mm F4.5-5.6 DG HSM II & Canon EF 24mm f/1.4L USM II at 24mm and the Sigma 12-24mm F4.5-5.6 DG HSM II and Tokina 11-16 f/2.8 at 11, 12, and 16mm. There are various types of comparisons to scroll through.
Overall image quality conclusions on a CROP sensor:-MUCH dimmer viewfinder compared to both other lenses
-Nearly as sharp as the $1700 prime Canon L lens in the center, not nearly as good in the corners
-Less CA than the Canon - really! Both have minimal CA, though
-Similar sharpness to the Tokina 11-16 - a tad better at some focal lengths/apertures, a tad worse at others
-Corners are better than the Tokina
-MUCH better CA than the Tokina
-Vignettes a bit at 12mm - and upper and lower apertures
-Pretty good flare resistance for an ultra-wide angle
-Compatible with Full Frame unlike the Tokina
-$300-400 more than the Tokina
The real test will be this weekend when I take it on a real shoot!