I'm trying to create an effect that shows a single screen, the camera then zooms out to show the screen in black space and a number of smaller screens emerge from behind, floating in the black space at different distances from the camera. Hope this makes sense, tricky to describe! There's an example of it here at 1:32 - http://www.aspectfilmandvideo.co.uk/showreel.html
Is this something I can achieve with an expression or will I have to animate each screen independently? Thanks for any help!
If it were AE alone, it would appear that they used a particle system.
But this is a demo reel for a good production house, so it's tough to know if that's the ONLY piece of software they used in that shot.
The whole idea behind a demo reel is to impress the viewer with one's capabilities. That's just one shot, taken from a longer piece of work, so it might also have been built in a 3D application... to make it easier to integrate into the portions of video that you DON'T see in that reel.
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA
You might want to take a look at PlaneSpace, from Red Giant. It allows you to do all sorts of effects along the lines of your reference, and will also allow you to animate size, position, and other aspects of your layers without keyframes: