As topic suggests... What would you choose? Could the 11mm be worth more than 2 stops of light? Or bokeh triumphs few steps of distance? Anyone to advise which one to choose? Price wise both are so close it's essentially the same.
Depends on what other lenses you have. If you have a 24-70 f/2.8, then switching lenses for one stop and a restricted zoom range does not save much. Or if you want a couple wider focal lengths like a 24 (or 35) and a 85, then you'll end up bring multiple lenses anyway. I can see that it is more useful for those that have more primes at other focal lengths or f/4 or slower zooms. But if I'm going to be taking off a 24-70 f/2.8, then I'd rather go with a f/1.4 prime.
First, there's a one-stop difference between them, not two. Second, it really depends on usage. If you're into landscapes, you'll appreciate being able to go wider, but if you're doing portraiture or events coverage, you'll appreciate that wider aperture.
I do have other lens, a 135mm F2 L USM, Tokina 16-28mm F2.8 and 50mm F1.8 II Canon. However, I'm asking the question to get better understanding of the performance itself, rather than focal length: which one autofocus better? Does one have much better colour than the other? Which one is a more pleasing lens? Does anyone have both of them and is ready to sell one off?
I do have other lens, a 135mm F2 L USM, Tokina 16-28mm F2.8 and 50mm F1.8 II Canon. However, I'm asking the question to get better understanding of the performance itself, rather than focal length: which one autofocus better? Does one have much better colour than the other? Which one is a more pleasing lens? Does anyone have both of them and is ready to sell one off?
Take a look at Dustin Abott's reviews:
http://dustinabbott.net/2015/08/sigma-24-35mm-f2-dg-art-review/
http://dustinabbott.net/2016/01/sigma-35mm-f1-4-dg-hsm-art-review/
The-Digital-Picture has also reviewed the Sigma 24-35, 24 and 35.
http://www.the-digital-picture.com/Reviews/Sigma-24-35mm-f-2-DG-HSM-Art-Lens.aspx
It is primarily a question of max aperture vs. focal length. If you need accurate AF, then the Canons are better. It is interesting to note that Dustin noted that he had much worse AF issues with the 35A than the 24-35, but there are others that claim that they have no issues with the 35A.
I had pretty bad AF issues with the 35, the dock was no help. The 24-35 is just as good as the 24-70f/4LIS and a bit better than the 24-105 in terms of AF speed and accuracy. Maybe I got a good copy, YMMV. I love this lens and it is part of my two lens creative bag, along with the 135L.