Awesome video, going viral as we speak. I just wanted to note how they did this. Basically a lot of chromakey, which is what James Cameron does when he wants to make the next highest-grossing film. You put someone in front of a screen that is one uniform color and lighting, and a computer can take it out for you and replace it with whatever. That “color” used to be blue but now it’s green because digital cameras are more sensitive to green. But the problem with digital is that it doesn’t really have the same range of tone and high resolution that film does, so you get less-than-perfect chromakeying:
You can see the green outline on the guy’s leg. But it’s a trade off between quality and convenience. Take a look here for Zacuto’s great camera shootout. It compares the quality of film and DSLR video. The consensus seems to be that film still beats digital, but digital is getting there. IT’S WOOOORRRRRKIIIIIING!
As for the camera movement in the dancing video, they probably motion tracked (computer analyzes camera movement and translate it into the movement of various coordinates) the initial camera movement, applied it to the different layers of dancers, and adjusted it in post. When various elements are combined into a seamless shot, it is called compositing. You can find some amazing examples of compositing in District 9. A good point Neill Blomkamp makes in this interview is how he made the effects look unimportant, for a more natural look. They’re just there.
It sort of takes you out of the movie when it seems to be trying to show off it’s special effects. Like in this next video, which actually took ten years to create the technology to film it.