Lack of imagination and herd mentality are two of the greatest curses of most human activity, especially including photography. One of the most annoying current cliches of commercial photography is the human figure (usually a girl) who is shown in extreme perspective distortion against a blank background, shot from almost directly above with a wide angle lens.

Let's talk about the physics of this type of shot. Someone who knows a little bit about photography might say that such photos are characterized by extreme depth-of-field. That is, for the woman on the right, her hand (very close to the camera) and her feet (many times further away) and all other points on her body appear to be in sharp focus. But “appear” is a key word. The depth of field of a photograph depends on the aperture of the lens, not its focal length. All lenses set to the same aperture should have the same depth of field, whatever their focal length. So why does the depth of field appear to be so large for a wide-angle lens? The answer is that wide angle lenses are generally used to produce images with extreme perspective... that is, the objects photographed are usually aligned roughly at right angles to the plane of the film. Thus, nearby objects appear huge in the frame and distant objects tiny. If one focuses on the nearest object, the fact that the distant objects are out of focus is generally not noticable, since they are so tiny in the frame. For discussions and demonstrations of this topic, look here and here.

Above we see two frame captures from scenes in the great Orson Welles film CITIZEN KANE. The visual style used throughout the film involves the illusion of infinite depth of field in each shot. Since it is optically impossible to get the background (at “infinite” distance) and objects in the extreme foreground (parts of faces) simultaneously in sharp focus, and since most shots mimic the appearance of a normal focal length (neither wide-angle nor telephoto), almost every shot in the film is baffling to anyone who knows anything about optics! There are many other optical jokes in each shot as well. Thus, in the captures above, the windows are seen in the first shot to be huge and very far from the camera, dwarfing Kane himself who stands below them. But when he advances a large distance toward the camera, he remains in focus and the background now suddenly appears to be of normal scale!

In each setup, the apparent infinite depth of field is an illusion, achieved by a huge arsenal of different special effects techniques. For instance, a shot where extreme foreground and extreme background are both impossibly in sharp focus might in a given case be achieved by a matte shot... that is, the foreground and background were shot separately by different cameras and combined on a optical printer. In other cases, matte paintings were used. [Chesley Bonestell worked on some of these matte paintings.] I'll leave you to guess a method for the setup shown above.... The cinematographer on CITIZEN KANE was the great Gregg Toland. Another master  cinematographer, Stanley Cortez, achieved a similar look in the fine Charles Laughton film NIGHT OF THE HUNTER--- you can see a number of the infinite depth-of-field tricks from KANE being used by Cortez in that later film.