Part of the beauty of the shallow depth of field that you can get with these new HD-DSLR cameras is that you can cause the viewer to look EXACTLY where you want them to by adjusting the focus accordingly. An in focus foreground causes the viewers to “focus” on the foreground. An in focus background with an out of focus foreground cause more attention to be paid to the background.
By adding this selective focus to an other wise static shot, you can actually move the viewer’s attention from one part of the screen to the other. All within the same shot!
This little trick of film making is called “Rack Focus”. By racking the focus from one plane in the scene to another, you can direct the attention of the viewer. It can also lend a dramatic flare to certain shots.
Here is a short video I did that demonstrates this cool little trick. Let me know what you think!