Introduction to One-Point Perspective chapter 6
This is a demonstration of the field of vision(also referred to as thecone of vision). The viewer is positioned in the center of
the photograph. His eye level forms the horizon line in the photograph, and he is transparent, so that you are able to see the
vanishing point through his head. The vanishing point remains constant as long as he stays in the same position. If he moves
to the left or the right, even slightly, the vanishing point changes. His eye level, of course, remains the same, as he cannot
change his height.
The figure in profile is the same person of the same height. He is standing on an artificial line on the ground, which is
referred to as the ground plane.Notice that as he is placed farther into the distance, he becomes smaller. However, his eye
level remains fixed at the horizon line because his eye level is identical to the viewer’s eye level.
If you take a strip of wood with the same height as your eye level and place it anywhere—some distance away from you—you
will notice that the top of the stick always remains on the horizon line.