Sigma 10-20 f/4-5.6 EX

Just thought I'd give a heads up on my experience with this lens. I picked one up because I really, really miss true superwide photography -- and it's quite difficult to get true superwide on a 1.6X crop camera like the 20D. In comes Sigma with their 10-20mm f/4-5.6 EX. Sigma catches a lot of crap for not being OEM, but they're capable of creating some quite capable lenses.. their 70-200 f/2.8 is excellent, as is (I hear) the new 100-300 f/4.

However, this lens, the 10-20, was a dud for me. It turned out to be quite clearly defective, with severe centering problems that caused objects in the righthand side of the frame to be soft... very, very soft. (The left side of the frame was quite nice and very, very crisp, leading me to believe that if you get a good copy of this lens, you'll be very happy.) This is a QC problem, as far as I'm concerned, as a lens producing such a flawed image never should have made it past the end of the assembly line. A little Googling reveals that this is actually not an isolated problem -- several other reviewers had the exact same problem that I did! Thus, I'm returning it and purchasing the Canon 10-22 3.5-4.5 instead. If there is one thing that Canon can be relied upon for, it's reliable QC. Well, that and inflated prices. But storm season is upon me and I don't have time to screw around playing the game of lens-swap.

So my advice on this lens would be to avoid it, or at least know that you're taking a risk that you'll get a defective lens if you do.
Sorry to hear you had a bad experience with the Sigma. I guess I'm biased, but I've always gone with Canon stuff, and its never been a disappointment yet.

Inflated prices? I don't know for sure, but I guess that's a matter for another discussion. It seems that what's true for many products is also true for photography accessories. You get what you pay for.
Wow, I had a completely different experience Ryan! I had a lot of articles about defective Sigma 10-20 mm's that exhibited focusing issues, but were rare to be gotten...this worried me, but I really wanted an ultra wide angle lens, and the Canon EF-S 10-22mm USM lens was way out of my price range for an UWA, and lots of people said the build quality seemed poor, and cheap, where as the Sigma was robust and sturdy. I just took a chance that I would get a 'non-defective' one.....and I got lucky...I got a perfect copy. It is a great lens for storm photography (if you get a good copy). I love the freedom it gives me, I don't feel so held back anymore....I guess it's all just chance. That's to bad they don't have better quality control.
I also have this lens in the Nikon mount for my D70, and I have not been displeased with it at all. The lens feels really good in your hand. I like whatever it is coated with. Of course, the pictures it takes are a little soft in the corners, but that is to be expected. Besides, it is so much fun to use that this doesn't matter.

Here's my favorite shot with it:

Personally, I can't wait to take this out on the Plains this spring! Sorry to hear you had such a poor experience with the lens, Ryan, though I'm jealous that you're getting the Canon (which is definitely far superior).
just ordered the 10 22 from canon so we will have to see I guess
just dont have time to deal with the potential pitfalls

now if I can get a trv 900 for UNDER A GRAND iLL BE STOKED (DAMN THESE ARE POPULAR)