When an observer is in motion, from side to side or vertically, distant objects will seem to move much slower than nearby objects. This is due to the distortion of length due to perspective.
Some neurological research suggests that motion parallax gives more depth-perception information than our binocular vision does,note thus a one-eyed person can still determine distance quite well if he moves his head a bit.
Thus, any truck or pedestal movement will reveal depth information not available to the single eye of the camera. It can call into question, very quickly, the flatness of a painted backdrop, either on set or in animation.
Live-action shows with windows on the set (and sufficient budgets) will often build the landscape outside as several layers of flat cutouts, thus giving some motion parallax to the background. This same idea was used to create pseudo-3D backgrounds for computer games during the 16-bit era when computers and consoles didn't have the horsepower for proper, textured 3D. A common bragging point on the boxes of many games is the number of simultaneously composited scrolling parallax layers the game displays at once.
To get around this problem in animation, some use multiple background cel layers, moving at different speeds. In the past this required a special piece of equipment called a "multiplane camera" but the effect has become much easier to manage in the digital age. Excessively cheap animation (see Filmation, Hanna-Barbera) uses the single Wraparound Background —the reuse of background images in a single scene to show movement— and this effect intensifies the fakeness.
Due to the astounding speed, vehicles traveling fast enough to produce Streaming Stars will not have parallaxes applied to them.
Contrast Skybox, rendering of a 3D game's sky as a cube that wraps around the world. Compare Squigglevision, giving the illusion of movement through exaggerated Line Boil, and Kinestasis, the panning and zooming of the camera over a still image to add some motion. Don't confuse with Parallax Montage, which are highly time-compressed advertisements.
Examples:
Anime & Manga
- Rebuild of Evangelion: Every monitor, particularly at the NERV headquarters and including non-plot-relevant ones, displays 5D parallax screens. This facilitates tracking where the Evas and Angels are in relation to each other but is mostly just Extreme Graphical Representation.
Gaming Consoles
- Nintendo 3DS: It's capable of producing adjustable, stereoscopic 3D visuals without the use of special glasses thanks to incorporating a parallax barrier on the top screen.
Films — Animation
- Bambi: The DVD extras go on to explain how the multiplane camera is employed to generate a feeling of depth through several layers of parallax. The characters in the foreground are animated at a different speed than the middle- and backgrounds whenever there are any Camera Tricks involved. More elements are made dynamic in certain scenes.
- In the Realms of the Unreal: The animated sections of Darger's magnum opus are generated through layered and panned kinestasis to produce a parallax effect. The cut illustrations are thus given a three-dimensional look.
- The Old Mill: As far as animation goes, this is the first short film recorded with a Multiplane Camera, then edge-cutting equipment that allowed shooting different pieces of artwork (of the backgrounds and characters) mounted on glass levels at different speeds. Thus resulting in an illusion of depth particularly exploited in the opening scenes.
Films — Live-Action
- Michael Bay: According to Lindsay Ellis's rundown of his film especial effects techniques, a wide parallax is part of his Creator Thumbprint.
- Spaceballs: The ships have a "Ludicrous Speed" mode that causes them to travel so fast, that motion parallax gets plaid.
Live-Action TV
- Corner Gas: The "at the top of the water tower" background in "Grad 68" is produced by a motion parallax layer between the tower proper and the scenery behind. It's a tad uncoordinated with the zoom, though.
Theme Parks
- Jurassic Park River Adventure: The Mosasaurus tank's screen has its scenery rendered by motion parallax to create a "seen through a camera lens" effect.
Video Games
- Agony (1992): The environments have three-layered parallax.
- Animal Crossing: New Horizons: Many of the wallpapers used to decorate your space (e.g., Chain-link Fence, Cherry Blossom Trees) are given the illusion of depth through slow parallax.
- Armor Alley: The scenic background is layered by parallax scrolling, although it's an optional feature that can be disabled if found distracting. You can also disable the scenic background altogether.
- Art Of Fighting 3: The background art is layered with parallax scrolling and sprite scaling to make it look more fluid.
- Astro Marine Corps: The 16-bit graphics are animated by one or two layers of parallax; one for the starts and another for any spacial debris or planets.
- Batman (Sunsoft): The game's detailed, fluid animation is partly achieved by parallax scrolling layered in the background artwork.
- Blazing Star: The second stage's first half has 3D parallax scrolling that runs at 60 fps. The sixth stage has a tunnel modeled with parallax that scrolls toward the foreground. In both cases, the effects are achieved through pre-rendered videos.
- Child of Light: The 2½D Ubiart Framework game engine builds the levels out of hundreds of 2D planes arranged in a 3D space. This makes complex parallaxes possible.
- Death Rally: Parallax movement can be seen on rock formations and buildings.
- Demotronic: Its first part features vertical parallax combined with rapidly changing color palettes to produce a unique 3D effect for the checkerboard that composes background. For it to be displayed, it requires cycle-perfect emulation.
- Devil Engine: A camera panning effect is achieved by means of parallax scrolling. It's a breathtaking swivel that occurs after defeating the fifth stage's mid-bosses.
- Doom 64: The skies are animated through parallaxes.
- Fatal Fury: Real Bout Fatal Fury and Garou: Mark of the Wolves have parallax scrolling enabling their backgrounds.
- Final Legacy: Employed along with other tricks to create a pseudo-3D look to the ship combat segments. The clouds, and birds flying over the ocean, are on two separate layers based on distance.
- Forbidden Forest: One of the earliest 2D games that uses parallaxes in its backgrounds.
- Golden Treasure: The Great Green: The scenery is illustrated by many-layered paintings that move at different speeds thanks to parallax techniques.
- Kentucky Route Zero: The parallax scrolling in act two's forest is an homage to René Magritte's "Le blanc-seing" ("The Blank Signature").
- Kirby's Adventure: There is complex motion parallax scrolling during the first phase of the final boss battle.
- Love Nikki - Dress Up Queen: A motion parallax effect is simulated by the main menu —the buildings in the foreground (Free Dressing and Store) move farther when swiping left or right than those in the middle ground (Recipe Workshop, Competition, and Stylist Association), and the buildings in the background (Stylist's Arena and Mystery House) less so than those in the middle.
- Mad Stalker: Full Metal Force: The Sharp X68000 version features motion parallax in the graphics of the layered backgrounds.
- Magical Taruruto-kun: The vividly colorful backgrounds of the video game adaptation are put in the spotlight thanks to the Sega Genesis's parallax scrolling.
- Major Stryker: The superimposed three backgrounds are generated through triple-parallax scrolling.
- Mayhem In Monsterland: The Commodore 64 are brought to a peak through, among other enhancements, the layering of parallax scrolling in some scenes.
- Mega Man:
- Mega Man 3: Although it cannot be seen through normal gameplay due to the console's technical constraints, the beginning of the Gemini Man stage has a planet with a ring system that is animated with parallax scrolling more complex than any other level.
- Mega Man: The Sequel Wars: Parallax effects are used to give the impression of the camera rotating around the platform for dramatic effect. They are also used in the compilation to improve the visual quality of the recolored backgrounds.
- Moon Patrol: This is the Ur-Example of the trope's use in 2D video games. There is only one parallax —the far background made of bluish rocky formations— that runs at a different speed than the brown-and-green foreground where the moon buggy is.
- Obitus: The aptly named Parallax Sections make use of several foreground and background layers of motion parallax that give the linear platform levels 3D depth.
- Pac-Land: The graphics of the platforms are given depth by means of parallax to distinguish them from the backgrounds. This is, however, not present in the TurboGrafx-16 version.
- Prehistorik Man: The GameBoy version has multiple, fully formed layers of parallax scrolling in the intro —the trees in front of Sam run faster than Sam and the text boxes he drags, which in turn move faster than the foliage in the background. The text boxes themselves are animated this way, although with no transparency, to allow their movement to be differentiated from Sam's.
- Prison City: To add onto the Retraux aesthetic, the backgrounds have parallax scrolling; although done in a cleaner way due to the advancement of display rendering technology.
- Putt-Putt: The DOS update of the Bear Stormin' minigame has scrolling grass, following the original demo version's lead which had much more simplified graphics.
- Shadow of the Beast: The otherworld sections in the original US Genesis port are rendered by motion parallax to create a sharp contrast against normal levels. Most other consoles have trouble replicating the effect.
- Shatterhand: The first part of area B boasts no less than four layers of parallax scrolling; which makes the backgrounds and other visual effects look very dynamic.
- Sonic the Hedgehog:
- Sonic the Hedgehog: At the time, the main draw to the game was the incredible graphics it displayed; half of it due to close attention to it and half owing due to the clever use of parallaxes that took into account Sonic's acceleration as well as vertical movement.
- Sonic 3 & Knuckles: On top of the usual ingenious use of this camera trick, the addition of scanline motion parallax allows for generating very dynamic water stages (particularly when near the surface, when the above and below backgrounds run at mismatched speeds) and smooths the two-player mode.
- Super Mario Maker: Most skins are layered with parallax which allows the characters of the retro ones to cast shadows on the background. It gives them the feeling of being illusions.
- The Byte Before Christmas: "Bell Hopper" is generated by fluid parallax scrolling despite the Atari 2600 being incapable of supporting such an effect.
- Vice: Project Doom: The train stage is rendered by eight levels of parallax scrolling in the background in order to fully capture the feeling of movement of a train. Since the NES consoles don't have parallax as the default, this was done by means of added software.
- Yomawari: Midnight Shadows: The tutorial is full of Scenery Porn achieved by layering the mountains with motion parallax so their depth is noticeable against the setting sun.
Western Animation
- My Little Pony: Friendship Is Magic: The animation is not done in traditional cels but rendered by an old version of Adobe Flash. Yet, it's still capable of being programmed to generate motion parallax and other non-CG 3D effects that prevent the middle- and backgrounds from looking flat.
Real Life
- In real life, and as stated in the description, motion parallax is a measurable physics phenomenon. It helps us calculate stuff like astronomical distances. For one, parsecs; i.e., the distance where the parallax angle is measured from opposite sides of Earth. For another, determining the distance of Stars is done by trigonometric parallax, which computes the relative movements of objects against a "fixed" background of far-off stars and galaxies. In other words, the closer a star is, the more it will seem to move, which is very noticeable when one does a star trail photograph.
