I've tried to do a couple of searches here but it usually leads to someone posting a link from ken rockwell and then everyone going off on ken rockwell.
The 3 lenses I was looking it was the tokina 11-16mm f/2.8 (which seems to be in backorder everywhere) the sigma 10-22mm, and the nikon 12-24mm f/4.
The nikon is overpriced (I'm a longtime canon shooter switching over, and the 10-22mm was my bread and butter), but I've heard good things about the 11-16mm f/2.8, and it's affordable and its nice to have that extra stop of light when your at the widest range. I havn't read much about the sigma though.
I've just got to Sigma 10-20 and so far it seems pretty decent. Nice Sigma EX build quality and nice and sharp. I also used to have the Sigma 12-24 and I really liked that too, but swapped for the 10-20 as it can take filters.
Personally I rarely shoot wider than f/8 on my wide angles so the f/2.8 of the Tokina doesn't appeal to me.
There is a nice comparison of the WA zooms on the nikonians site that you might want to take a look at, especially if you plan to use the lens a lot. IIRC, it compares the sigma, nikon and tokina zooms. Sorry, I don't have a link.
I have and like the sigma 10-20, but I'm not much of a WA shooter.
if you ever plan to go full frame in the future, you may as well get the 14-24mm.. Used, they are going pretty cheap because many people bought it new, figured out that they never use it or its too big, and want to dump it
I see them on craigslist as low as $1100 or even less...
If I were shooting crop Canon, the 10-22 is best IMO, but only if you don't need the extra F-stops. If that were the case, the Tokina 11-16 would be my choice. I had the 11-16 Tokina for the first few months it was out and loved it. Sharp, accurate focus even in lower light and solid as a rock.
If I were shooting Nikon the 14-24 on FF and the Tokina 11-16 on a crop are the best options IMO.
Nothing Canon makes even approaches the 14-24. Nothing anyone makes for that matter.
Best optical quality and resistance to flare (main difference) -> Nikkor 12-24
Normal UWA high quality at a reasonable price -> Tokina 12-24 (my personal choice)
Real UWA -> Sigma 10-20 (I have seen a LOT of very convincing pictures but the Sigma grey finishing is really not my favorite - peeling off and not scratch resistent)
Need for speed (2.8) -> Tokina 11-16
I don't know about the new Tamron, but some people seem to like it...
I've seen a lot of great stuff said about the Tokina 11-16, that it rivals the Nikon for overall sharpness. Seems like the problems I've seen mentioned about it had to do with the early Canon versions. Here's a good resource: http://www.pixel-peeper.com/
I love the Tokina 12-24, although its only 18mm FF equivalent, which is wide not ultra wide. The Sigma 10-20 is loved by many, but I just didn't like the look or feel of it, and I need 20-24 more than 10-12.
