Over-used background film effect

[Will__]

There's a very over-used effect that involves the foreground staying the same (usually an actor being surprised or shocked) while the background recedes away. How is this achieved?

[Hippy]

This effect relies upon the changing focal length of a zoom lens. The trick is to move the camera at the same time as zooming, so that the actor stays the same size in the frame.

So say you want the background to appear to increase in size you would zoom in (increase the focal length from wide angle to telephoto) whilst rapidy moving the camera away from the actor. To make the background appear to slip away into the distance do exactly the reverse. It needs a lot of practice for the people pulling the camera dolly at a certain rate whilst the focus puller operates the zoom at just the right speed.

[inferno]

I think ther effect was first used in Jaws

[Phantaxus]

I think you will find it was first used in Vertigo

[lisaj]

Hippy: it used to require a lot of practise. Now the focus and dolly movements can be motorised to run at a certain spede over a certain timeframe, allowing perfect synchronisation.