Urgh. That's pretty horrible. Just boosts my opinion that the Canon really is the only lens to consider if this sort of shooting is at all important.
I must have had a bad 10-22 then... the Canon I had was much worse... given the example above, with my Canon, the flare would have started on the left side where the sun is, and it would spread at least halfway through the frame... the Tokina had wasn't much better than the Canon... the Sigma is the best I've had. Not to mention the contrast and color reproduction... the Canon's colors were always a bit flat.

