Sigma 500mm f4.5 with TC's?

Can the 500mm fv.5 be used with TC's and still retain AF? I am under the impression not, as AF is only available at f4?

Here you go

http://www.sigma-photo.co.jp/english/support/faq/condaitr.htm

Sigmas list is not totally 100% accurate though .. my 100-300mm f4 used to AF with the 2x (although speed took a big hit). They do seem to err on the side of caution.

I would imagine the 1.4x will ... the 2x probably not.

cheers
Since 500 f4.5 shows no AF on either TC then it looks like I'm going to have to go Nikon for a long lens, was hoping to upgrade to a K-5 and use the sigma but it may have to be a Nikon 500 f4 because i want the flexibility of that extra bit of reach

I have a Sigma 500mm f4.5 EX DG, and yes it will AF with a 1.4x tc

I can also vouch for that. Surprisingly well too!