The parallax effect is the visual phenomenon where objects at different distances from the camera appear to move at different speeds relative to one another as the camera moves through space. Near objects seem to pass quickly while distant objects move slowly, creating the perception of depth and three-dimensional space from a two-dimensional image. This differential motion between foreground, midground, and background layers is how the human visual system understands spatial depth during movement.

In filmmaking and visual effects, the parallax effect is used deliberately to enhance the sense of depth and spatial presence in shots. Camera movement that passes near foreground elements and reveals depth behind them creates a strong sense of physical space that static shots cannot match. In post-production, the parallax effect is simulated by animating layered still images at different speeds, a technique used to create apparent camera movement from photographs in documentary and archival footage contexts. In 3D rendering and game engines, parallax is naturally produced by perspective projection as the virtual camera moves.

AI video generation models trained on real-world footage have absorbed the visual conventions of parallax as part of what makes moving footage look physically believable. Prompting for camera movements through layered environments - a tracking shot through a forest, a push through a crowd, a dolly through an architectural space - tends to produce parallax naturally when the scene description suggests sufficient foreground-to-background depth. Explicitly describing layered environments with near and far elements can help reinforce this effect.