I've been extremely pleased with my Sigma 8-16 on the Cinema Camera. A *lot* less angular distortion than my Canon 8-15mm and my Rokinon 8mm and doesn't seem to show any barrel distortion at all. It's a bit slower than I'd like, and it definitely doesn't have the build quality as the Canon, but it works great and even at 8mm I can still mount my ARRI MMB-1 mattebox, which was designed to go very wide. Couple that with the fact the MMB-1 is perfectly aligned with the Viewfactor cage (as I mention with
photo on my Facebook page), everything is basically a really well matched system together. Really, really nice. We actually ended up using the Sigma 8-16 quite a lot for the shoot.