Not a thorough review, just a few snaps in the park but I think you'll get an idea of how good this lens is:
CLICK HERE
Much more satisfying than the Canon 17-40L that I returned.
Remarkable!!!!
Very acceptable indeedy!!!!
Nice piece of glass, Mitch!
Why did you return the Canon 17-40L? I always thought Canon made the best lenses - the rest are just imitations.
Let's see... very poor autofocus in low light (not just hunting but consistent mis-focusing), not sharp at f/4 (my comparisons suggest the Sigma is sharper at f/2.8 than the Canon at f/4), and not much better at f/8.
At comparable focal lengths, my Canon 28-135 IS lens was sharper. So was the Tamron 28-75 f/2.8 XR Di.
So, in a nutshell, it did not live up to the hype.
It's very possible I got a bad copy, but I've read very similar comments about this lens on the web. Maybe Canon has some QC problems because it's such a big seller.