Which wide-angle lens should i choose?

stephan902 wrote in post #10675126
Why?

Why not the Canon for example?

Besides being expensive, if you believe the MTF graphs at lenstip.com the Canon's reslution is optimized at 17-22mm and not nearly as good at 10mm. The Tokina 10mm-24 (for one) is optimized for 10mm, and just okay from there on. Of course other issues exist with the Tamron that might make it a bit weaker than the Canon (gotta stop the Tamron down to get even decent quality). The same exists but is less intense on the Canon. Wide angle lenses seem to be all over the place in terms of quality and performance. It certainly isn't clear which is best for everything. If only we could buy them all and meld them Syfy-like. (Can you tell it's Syfy Friday?)

Here are the MTF charts I spoke of
Canon: http://www.lenstip.com …USM_Image_resol​ution.html

Tokina:http://www.lenstip.com …IF)_Image_resol​ution.html

Based on this, a person might want to choose between the two lenses depending on if they mostly need 10mm shots or mostly need 17-22mm shots.

Update: I should note that I own the Canon, and I'm not a huge fan. It's great sometimes and a huge disappointment at other times....although if it were a $200 lens, I'd be ecstatic with it.

IMO, I'd say that the Tokina 11-16mm is the best UWA lens for cropped camera bodies. But you can't go wrong with the Tokina 11-16, Tokina 12-24 OR the Canon EF-S 10-22.

So you can say that the Tokinas are both good and the Canon is at well.

Then i guess i would go for the new Tokina as it is much cheaper than the Canon and i would have to buy an extra hood for the Canon.

But finally i cant really decide between: Tokina 12-24mm II, Tokina 11-16mm, Sigma 10-20mm 3.5

I have had the same issue a few months ago. I wanted ultrawide, but didn't want to spend a huge amount of money on it. Based on the reviews and user experiences I've read online, the Canon 10-22 would be my best choice. It is priced somewhere around $750 / 700 euros though, a lot more than I would want to spend.
Tokina's 12-24 would also be great, but I would really prefer 10mm over 12mm. Tokina's 11-16mm is really great for low-light, but with its limited range I could already imagine myself switching lenses all the time.
Sigma's 10-20mm would be the more affordable choice, but from what I've read it's slightly less in performance compared to the Canon. But at least it would be affordable to me when buying it brand new...

So, my options were a new Sigma 10-20mm f/4-5.6 or a used Canon 10-22mm. Sigma also has the more expensive f/3.5 version, but that one appears to be not as sharp as the f/4-5.6 but does give you a wider aperture that might be useful for low-light.
I ended up buying the used Canon 10-22mm, and I really have no regret! Great contrast, really vibrant colors, it's all there.

The hood didn't come with it (previous owner shared it with an other lens he kept so he also kept the hood), but a knock-off EW-83E costs just a few bucks on ebay.

Whichever you'd prefer would be up to you I guess. Would you need the f/2.8 of Tokina's 11-16mm, or would you prefer the extra range of Tokina's 12-24mm, or the extra wide-angle of Sigma's 10-20mm? If image quality is high on your list, I'd advise you to go with any of the Tokina's. From what I've seen they are simply amazing in IQ, which I have not seen beaten by either of the two Sigma 10-20's.
If buying a second-hand lens would be fine, I'd advise you to try and obtain a used (not too old) Canon 10-22mm for a reasonable price. That's what I did, and I'm still very happy with it!

Either one you pick will be great but I'm bias I like Tokina over sigma because of my experience with them. I also prefer the built of the Tokina.

The Tokina 11-16 is great because it's wide and fast because it has a max aperture of f/ 2.8 and it's constant. The Tokina 12-24 is also great because it's also wide, constant aperture of f/4, and it's cheap. The sigma is great because it's wider than everything else and it has HSM.

Here are some tests to look at: http://www.pbase.com/l​ightrules/lenstests