Miniature Faking - Some General Characteristics of Images

Some General Characteristics of Images

In a typical scene, objects close to the camera are at the bottom of the image, and objects far from the camera are at the top. This is less true if the image includes significant height as well as depth; a tall object near the camera can extend the height of the entire image.

Only one plane can be in precise focus. Objects not in the plane of focus are blurred; the blurring increases with distance from the plane of focus. But blurring less than a certain amount is imperceptible under normal viewing conditions; objects for which blurring is imperceptible are within the depth of field (DoF).

DoF decreases as magnification increases; in a close-up photograph of a miniature scene, the DoF is limited, and it often is impossible to have everything appear sharp even at the lens's smallest aperture. Consequently, the foreground and background are often blurred, with the blur increasing with distance above or below the center of the image. In a photograph of a full-size scene, the DoF is considerably greater; in some cases, it is difficult to have much of the scene outside the DoF, even at the lens's maximum aperture. Thus a difference in DoF is one characteristic by which a photograph of a full-size scene is readily distinguished from one of a miniature model.

In typical photographs, there are no optical cues that specify the distance to objects (how far they are from the observation point) and so distance has to be inferred from the size of familiar objects in the scene. DoF blurring is a visual cue to distance. In a diorama illusion, the introduction of the blur cue appears to override this familiar information causing objects to appear miniature and toy-like.