Mods If this is in the wrong forum, feel free to move it. I have my new D7000 and just tried my Sigma 10-20, and Tamron sp 70-300. Both auto focus when using the viewfinder, however they dont auto focus in live view. Whats up? Thanks.
Many third party lenses manufactured before Nikon released the D7000 don't work with the live view mode contrast detect autofocus on the D7000. I know that is the case with the 10-20. Sigma can upgrade the lens to work with live view. You'll need to contact them.