Depth and Movement in the Frame
Visual media exist in two dimensions. Whether on a theater movie screen, a computer monitor, or a TV set, the image has height and width (its aspect ratio) but no depth beyond the measurement of light molecules or pixels. Three-dimensional movies and television (discussed later) are an illusion of three-dimensionality displayed on a two-dimensional screen. In geometry, we call the width the x-axis, the height the y-axis, and the depth the z-axis (Figure 4.1).
Despite the fact that the images we deal with have only two dimensions, most of what we portray in these images is made up of three-dimensional objects. To view these objects as three-dimensional entities in a two-dimensional medium, ...