p.1 #2 · Does Sigma extender works with Tokina lens?
Even if it fits, you're talking about creating an f/11 lens that surely won't autofocus and will want to be stopped down a couple of stops from wide open--which suddenly is at f/22. Not a good idea.
I've had the Tokina in Canon mount and it was a remarkably good lens for the price. I would not suggest it with a 2x TC, though.
