It seems that all of these threads play out the same way, with some lamenting the AF issues with
the Sig 50 and others raving about how theirs has never had a problem. I tend to believe both
camps. I happen to be one who has had problems. Sigma had my lens and my Canon 5D body
for about a month and after speaking with the supervisor who assured me it was in the best
condition he could get it, they sent it back. It seems to be about the same as when I sent it in.
I don\'t worry about it much anymore. I treat the lens as one that can really deliver the goods
if I baby it and focus-bracket and such. Frankly, I still think it\'s a good lens, but yes it has
made me reluctant to even bother trying the Sig 85, even though I\'d love a great 85/1.4 with AF.
But that\'s it: It needs to have reliable AF, and for the moment I\'m not interested in rolling the
dice to see if Sigma got it right. I am happy for those whose copies are great. [This is not just
a Sigma issue either. I am reluctant to buy a lot of high-precision gear these days -- Canon
included, because it does, in my experience, require testing and occasional trips to service to
get tip-top performance.]
By the way -- my Sigma 150/2.8 macro works fine, so Sigma sometimes gets it right too. I\'m
not trashing Sigma.
In short: Optically the 50 is a great lens; AF wise, it\'s hit and miss for many of us.
