Movement parallax refers to the fact that the view of a scene changes with movement of the head. Thus, different images of the scene are seen as the head is moved from left to right, and from up to down.
Many autostereoscopic displays are single-view displays and are thus not capable of reproducing the sense of movement parallax, except for a single viewer in systems capable of eye tracking.
Some autostereoscopic displays, however, are multi-view displays, and are thus capable of providing the perception of left-right movement parallax.[32] Eight and sixteen views are typical for such displays. While it is theoretically possible to simulate the perception of up-down movement parallax, no current display systems are known to do so, and the up-down effect is widely seen as less important than left-right movement parallax. One consequence of not including parallax about both axes becomes more evident as objects increasingly distant from the plane of the display are presented, for as the viewer moves closer to or farther away from the display such objects will more obviously exhibit the effects of perspective shift about one axis but not the other, appearing variously stretched or squashed to a viewer not positioned at the optimum distance from the display.