The dolly zoom was developed by Alfred Hitchcock and is one of the most recognizable cinematic camera techniques first used in the movie Vertigo, and it is still being used in films today to give the feeling of disjunction, shock, alienation. The movies Jaws and Goodfellas have excellent examples of using a dolly zoom if you want to see how it was effectively used by master directors Spielberg and Scorsese.
The fundamental technique of a dolly zoom is simple, you move the camera back while adjusting the zoom so the subject stays the same size on the screen. So you may be asking yourself ‘why did it take so long to develop this technique?’ Well, the answers is due to the lack of technology. In order to create the visual effect you have to use a smooth mechanical zoom which wasn’t available until around the time Vertigo was produced. If you try to do it by hand you’ll soon realize why it wasn’t possible until the mechanical zoom was up up par. To setup your equipment to do the dolly zoom you really only need to have your camera and a dolly. The rest of it is all technique and it takes a lot of practice to get it right. They key is to match when motion of the dolly and the zoom so it looks like your subject is in the same place while the background is changing due to the camera moving. The dolly zoom is really difficult to master so if you don’t get it right away keep practicing and you’ll eventually get the hang of it.