back to TS question. I think he's looking at the Tokina's f/2.8 is for the "better bokeh" that larger aperture lens offers...maybe TS wanted a UWA zoom lens that can take snapshots of people without walking way back to put the whole of them in the frame?
I personally does that at times, especially with my kids as they like to put their face right up infront of the lens...
In fact for wide angle lenses or UWAs, having a small aperture ain't necessary for bokehs.
Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.
It's really tough to get bokeh from a UWA lens... And it's really tough to tell the difference between the bokeh at f/2.8 and f/3.5.
Halo to all,
Thanks for all the advice given so far and its good to know some things from another angle of view.