AF on Tamron SP 70-300 F/4-5.6 Di VC USD

Quick question:
I just got the Tamron SP 70-300 a few days ago. Concerning the focus ring, is the ring supposed to turn when in AF? The lens is focusing, but the focus ring isn't turning. I watched a YouTube video and the focus ring on that one wasn't turning either. Like I said no problems with focusing, the numbers underneath the glass window are moving normally, the subject in the viewfinder is coming into focus, it's jsut the focus ring isn't moving while lens is focusing.
Thanks,
Randall

I'm still new to this, so I don't know much about the filter thing, but based on your response I assume my lens is working normally?

The focus ring does not turn during AF. You can manually override focusing during AF by turning the focus ring though.

In short, this is a good thing. Excellent lens too. Enjoy.

Thanks.

your lens works fine. it's internal focus so the ring doesn't turn which is a good thing.

Actually, internal focusing means that the front element doesn't rotate on focusing which means you can more easily use polarizing filters. Your lens has USD (Tamron's version of Canon's USM) with full-time manual focusing. This means you can turn the focus ring manually at any time and override the autofocus if needed. This is a good thing.