Canon EOS 450D Autofocus problem

[jetskidia]

Canon EOS 450D Autofocus problem.

Hi
I've got a 450D.
With my Canon 18-55 lens all is ok, but with my Sigma 100 -300 the camera tries it hardest to focus but it cant get it perfect so wont take a picture.
In Man focus all is ok.
Any ideas please guys?
Thanks

[LongQ]

FWIW a quick Google turned up a number of forum threads about AF problems with the Sigma lens, amongst them this one. Not all were Canon related.

http://www.thephotoforum.com/forum/beyond-basics/2...

So far I have not seen anyone with a problem bother to report back as to whether they have a resolution. Maybe I have just read the wrong threads.

However, given the Af works with teh Canon lens but not the Sigma lens it may be more accurate to think of the problem as an AF issue with a Sigma lens rather than with a 450D for the time being.

Edited by LongQ on Saturday 3rd July 00:26