Sigma 50 1,4 AF inaccuracy when AF Assist

[zerartul]

I noticed my Canon Mount Sigma 50 1.4 has a serious case of AF inaccuracy only when AF Assist is fired? Is it a common problem and is it rectifiable? Its not a huge problem since its a low light lens and can AF usually without assist but just want to know if any one else is having that problem and if it can fixed by Sigma Service. Also at infinity is seems to have a low af hit rate (50%). Do people recommend to send in calibration for it?

 

[wrx_sti_22b]

Read this : http://www.clubsnap.com/forums/showpost.php?p=5127157&postcount=5

 

[zerartul]

Hmm Im actually looking for the Flash AF Assist issue. Seem to plague my 40d bad whenever i use flash af assist. My normal focus is just a tiny bit out. Probably will send to sigma to do the final touch to it for perfection when i have time.

 

[mckenzy]

quick question... did the lens exhibit this issue at the shop where you bought it? or did it develop over time?

 

[lightrules]

Quite common with Sigma lens
not the camera problem.
Happens with sigma 12-24 too