Just a real quick test of the Sigma 18-35 with the Canon C100 in my neighborhood.
Wide DR Profile
First 3 shots were handheld and slightly stabilized with AE
Just minor contrast and slight saturation, and slight sharpening added in post with Magic Bullet.
Last shot was indoors at 1.8 so you could see the DoF
The lens is very nice, very solid and very smooth to focus with. Handheld was a little shaky, but that could have been me :)


Sigma 18-35 test - Canon C100 on Vimeo

Hey Dan, have you had any issues with your autofocus? My autofocus seems to only work when I'm wide open at 1.8.

The few times that I have used this lens for stills on my 550D I have not noticed any problems with autofocus.
It is on my C100 when I do use it, and that is with manual focus, so I can't say from there.
Sorry!