What video effect is this?

Question

I'm not sure if it's a video effect or a camera effect but watch this video:

http://www.youtube.com/watch?v=o7_LXExvmQo

Now from 00:22~00:25, the background is blurry but the girl is sharp and clear. Is this is a video effect or a camera effect? And if it's a video effect, what's it called, and can my Sony Vegas Pro 8 do the trick?

Answer 1

It's none of the two.

Manual focus was used. That's all. The cameraman focused on the nearest object (the girl) and it blurred the background.