movie auto focus with DSLR

Here's a hand held movie clip capturing a slice of humanity on the streets of Saigon in the build up to xmas 2010. It demonstrates focussing of the EOS 7D done manually just using the ring on the lens and my bad eyesight looking at the camera's live view screen. I'd need a third hand for zooming at the same time, so there's none.

Now for an interesting comparison with Sony's SLT a33, which is one of the first dslr's to have auto focus in movie mode, here's an example I found online:

http://vimeo.com/15917919

With the Sony, you can zoom and focus at the same time obviously. A downside is the phase change AF system requires the maximum lens aperture to operate, so the depth of field is minimised. Still, that means you'll be achieving that cinematic look most people are after....also, was that noise on the Sony clip (...apart from the wind), the auto-focus engine?