Since using my 70-200mm ex dg sigma over the last couple of days there has been several times when I lose auto focus?..What I mean is when I half press shutter button it does nothing..its as if its froze but can still see image in viewfinder and all other controls work..any ideas? This has happened in af-s and af-c mode..rang sigma and they had no idea.Would it be the lens or the camera?.Hasn't occurred with any other lenses
If you're not getting any error messages - turn off the camera, take off/put back on, and turn the camera back on. It will work fine. I had the same problem with the one I had, and it had something to do with the contacts, and F-mount/weight of the lens. With the lens attached, is there any play? can you "wiggle" the entire lens?
If the above works, but you can't live with it - then send it back to Sigma to replace the mount. Otherwise, get rid of it and get the 70-200 VR (if you can), or the 80-200 2.8 if money's tight. There are still a few 80-200 2.8 AF-S lens out there that dealer's weren't able to sell. I picked one up for just over $1K, U.S., Warranty Cards, Manual, Lens Case, and Box - got it from a small dealer in Canada. The box was a little tattered, but everything else was 5/5.
Best of Luck, and hope this helps.
Art
PS - Nikon Service rocks! Sent in my 2H 9 days ago, and just got it back today - out of warranty, no charge, and they replaced all the rubber, and front aperture dial.
Cheers guys..yes there is a little play where the lens meets the camera and also have this on my 150mm macro...I did hear that all the sigmas "wiggle" a little on the nikon camera but don't know how true that is?.
Joshua I thought the link you provided was only for the D200 problems with certain hsm lenses not the d70?
