Hello, I just recently bought a new Nikon D3100 and am looking to upgrade the kit lens. Here's what I'm looking for: -max aperture f/2.8 -VR/VC/OS feature -mid range "street" lens The Tamron 17-50mm VC fits all of the above (and my budget) but I have read from a few sources that the lens lacks an internal focusing motor. Does the Tamron 17-50mm VC have an internal focusing motor? The entry level D3100 does not have a focusing motor built into the body so if I got a lens without an internal motor I'd be shooting blanks. Thanks for any help and I'm also open to other lens suggestions.