Motion control camera dolly with Canon DSLR camera
Motion control photography is a technique used in still and motion photography that enables precise control of, and optionally also allows repetition of, camera movements. It can be used to facilitate special effects photography. The process can involve filming several elements using the same camera motion, and then compositing the elements into a single image. Other effects are often used along with motion control, such as chroma key to aid the compositing. Motion control camera rigs are also used in still photography with or without compositing; for example in long exposures of moving vehicles.[1][2] Today's computer technology allows the programmed camera movement to be processed, such as having the move scaled up or down for different sized elements. Common applications of this process include shooting with miniatures, either to composite several miniatures or to composite miniatures with full-scale elements.
The process is also commonly used when duplication of an element which cannot be physically duplicated is required; motion control is the primary method of featuring multiple instances of the same actor in a shot that involves camera movement. For this technique, the camera typically films exactly the same motion in exactly the same location while the actor performs different parts. A blank take (with no actor in the shot) is sometimes also taken to give compositors a reference of what parts of the shot are different in each take. This, in common film-making language, is also known as shooting a "plate".
In today's film, the reference take is also useful for digital manipulation of the shots, or for adding digital elements. A simple duplication shot confines each "copy" of an element to one part of the screen. It is far more difficult to composite the shots when the duplicate elements cross paths, though digital technology has made this easier to achieve. Several basic camera tricks are sometimes utilized with this technique, such as having the hand of a body double enter a shot to interact with the actor while the duplicate's arm is to be off-screen. For the sake of compositing, the background elements of the scene must remain identical between takes, requiring anything movable to be locked down; the blank reference take can aid in resolving any discrepancies between the other shots.
Similar technology in modern film allows for a camera to record its exact motion during a shot so that the motion can be duplicated by a computer in the creation of computer generated elements for the same shot.
History
Modelmaking for scenery has long been used in the film industry, but when a model is too small it often loses its illusion and becomes "obviously a model". Solving this by building a larger model introduces a dilemma: larger models are more difficult to build and often too fragile to move smoothly. The solution is to move the camera, rather than the model, and the advent of compact lightweight 35mm cameras has made machine-controlled motion control feasible. Motion-control also requires control over other photographic elements, such as frame rates, focus, and shutter speeds. By changing the frame rates and the depth of field, models can seem to be much larger than they actually are, and the speed of the camera motion can be increased or decreased accordingly.
Early attempts at motion control came about when John Whitney pioneered several motion techniques using old anti-aircraft analog computers (Kerrison Predictor) connected to servos to control the motion of lights and lit targets. His film Catalog (1961) and his brother James Whitney's film Lapis (1966) were both achieved with John's pioneering motion control system. The 1968 film 2001: A Space Odyssey pioneered motion control in two respects. The film's model photography was conducted with large mechanical rigs that enabled precise and repeatable camera and model motion. The film's finale was created with mechanically controlled slit-scan photography, which required precise camera motion control during the exposure of single frames. The first large-scale application of motion control was in Star Wars (1977), where a digitally controlled camera known as the Dykstraflex performed complex and repeatable motions around stationary spaceship models. This enabled a greater complexity in the spaceship-battle sequences, as separately filmed elements (spaceships, backgrounds, etc.) could be better coordinated with one another with greatly reduced error.
In the UK The Moving Picture Company had the first practical motion control rig. Designed and built in-house in 1981, it used the IMC operating system to control its various axes of movement. Peter Truckel, MPC's first in-house VFX supervisor, operated it for several years before leaving to pursue a career as a successful commercials director.
The simultaneous increase in power and affordability of computer-generated imagery in the 21st century, and the ability for CGI specialists to duplicate even hand-held camera motion (see Match moving), initially made the use of motion control photography less common. However film producers and directors have come to realise the cost-saving benefit of using motion control to achieve the effects in a reliable and realistic way. CGI still struggles to be 100% photorealistic, and the time and cost to achieve photo-realistic shots far exceeds the cost of shooting the live action itself.
With the resurgence of 3D as a medium motion control has also an important role to play, especially in the production of 3D background plates on scaled-sets. Using high resolution still cameras, backgrounds can be easily shot for further use with live action and CGI character animation.
A miniature effect is a special effect created for motion pictures and television programs using scale models. Scale models are often combined with high speed photography or matte shots to make gravitational and other effects appear convincing to the viewer. The use of miniatures has largely been superseded by computer-generated imagery in contemporary cinema.
Chroma key compositing, or chroma keying, is a visual-effects and post-production technique for compositing (layering) two or more images or video streams together based on colour hues. The technique has been used in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture, and video game industries. A colour range in the foreground footage is made transparent, allowing separately filmed background footage or a static image to be inserted into the scene. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as colour keying, colour-separation overlay, or by various terms for specific colour-related variants such as green screen or blue screen; chroma keying can be done with backgrounds of any colour that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most distinctly in hue from any human skin colour. No part of the subject being filmed or photographed may duplicate the colour used as the backing, or the part may be erroneously identified as part of the backing.
Special effects are illusions or visual tricks used in the theatre, film, television, video game, amusement park and simulator industries to simulate the imagined events in a story or virtual world. It used to be called SFX but this short form has also expanded to include “sound effects” as well.
Bullet time is a visual effect or visual impression of detaching the time and space of a camera from that of its visible subject. It is a depth enhanced simulation of variable-speed action and performance found in films, broadcast advertisements, and realtime graphics within video games and other special media. It is characterized by its extreme transformation of both time, and of space. This is almost impossible with conventional slow motion, as the physical camera would have to move implausibly fast; the concept implies that only a "virtual camera", often illustrated within the confines of a computer-generated environment such as a virtual world or virtual reality, would be capable of "filming" bullet-time types of moments. Technical and historical variations of this effect have been referred to as time slicing, view morphing, temps mort and virtual cinematography.
Visual effects is the process by which imagery is created or manipulated outside the context of a live-action shot in filmmaking and video production. The integration of live-action footage and other live-action footage or CGI elements to create realistic imagery is called VFX.
Traditional animation is an animation technique in which each frame is drawn by hand. The technique was the dominant form of animation in cinema until the end of the 20th century, when there was a shift to computer animation in the industry, specifically 3D computer animation.
Computational photography refers to digital image capture and processing techniques that use digital computation instead of optical processes. Computational photography can improve the capabilities of a camera, or introduce features that were not possible at all with film-based photography, or reduce the cost or size of camera elements. Examples of computational photography include in-camera computation of digital panoramas, high-dynamic-range images, and light field cameras. Light field cameras use novel optical elements to capture three dimensional scene information which can then be used to produce 3D images, enhanced depth-of-field, and selective de-focusing. Enhanced depth-of-field reduces the need for mechanical focusing systems. All of these features use computational imaging techniques.
Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live-action shooting for compositing is variously called "chroma key", "blue screen", "green screen" and other names. Today, most, though not all, compositing is achieved through digital image manipulation. Pre-digital compositing techniques, however, go back as far as the trick films of Georges Méliès in the late 19th century, and some are still in use.
In visual effects, match moving is a technique that allows the insertion of 2D elements, other live action elements or CG computer graphics into live-action footage with correct position, scale, orientation, and motion relative to the photographed objects in the shot. It also allows for the removal of live action elements from the live action shot. The term is used loosely to describe several different methods of extracting camera motion information from a motion picture. Sometimes referred to as motion tracking or camera solving, match moving is related to rotoscoping and photogrammetry. Match moving is sometimes confused with motion capture, which records the motion of objects, often human actors, rather than the camera. Typically, motion capture requires special cameras and sensors and a controlled environment. Match moving is also distinct from motion control photography, which uses mechanical hardware to execute multiple identical camera moves. Match moving, by contrast, is typically a software-based technology, applied after the fact to normal footage recorded in uncontrolled environments with an ordinary camera.
The Computer Animation Production System (CAPS) was a proprietary collection of software, scanning camera systems, servers, networked computer workstations, and custom desks developed by The Walt Disney Company and Pixar in the late 1980s. Although outmoded by the mid-2000s, it succeeded in reducing labor costs for ink and paint and post-production processes of traditionally animated feature films produced by Walt Disney Animation Studios (WDAS). It also provided an entirely new palette of digital tools to the animation filmmakers.
Time-lapse photography is a technique in which the frequency at which film frames are captured is much lower than the frequency used to view the sequence. When played at normal speed, time appears to be moving faster and thus lapsing. For example, an image of a scene may be captured at 1 frame per second but then played back at 30 frames per second; the result is an apparent 30 times speed increase. Similarly, film can also be played at a much lower rate than at which it was captured, which slows down an otherwise fast action, as in slow motion or high-speed photography.
Mattes are used in photography and special effects filmmaking to combine two or more image elements into a single, final image. Usually, mattes are used to combine a foreground image with a background image. In this case, the matte is the background painting. In film and stage, mattes can be physically huge sections of painted canvas, portraying large scenic expanses of landscapes.
A front projection effect is an in-camera visual effects process in film production for combining foreground performance with pre-filmed background footage. In contrast to rear projection, which projects footage onto a screen from behind the performers, front projection projects the pre-filmed material over the performers and onto a highly reflective background surface.
Rear projection is one of many in-camera effects cinematic techniques in film production for combining foreground performances with pre-filmed backgrounds. It was widely used for many years in driving scenes, or to show other forms of "distant" background motion.
Virtual cinematography is the set of cinematographic techniques performed in a computer graphics environment. It includes a wide variety of subjects like photographing real objects, often with stereo or multi-camera setup, for the purpose of recreating them as three-dimensional objects and algorithms for the automated creation of real and simulated camera angles. Virtual cinematography can be used to shoot scenes from otherwise impossible camera angles, create the photography of animated films, and manipulate the appearance of computer-generated effects.
When creating computer-generated imagery, final scenes appearing in movies and television productions are usually produced by rendering more than one "layer" or "pass," which are multiple images designed to be put together through digital compositing to form a completed frame.
Previsualization is the visualizing of scenes or sequences in a movie before filming. It is a concept used in other creative arts, including animation, performing arts, video game design, and still photography. Previsualization typically describes techniques like storyboarding, which uses hand-drawn or digitally-assisted sketches to plan or conceptualize movie scenes.
The history of computer animation began as early as the 1940s and 1950s, when people began to experiment with computer graphics – most notably by John Whitney. It was only by the early 1960s when digital computers had become widely established, that new avenues for innovative computer graphics blossomed. Initially, uses were mainly for scientific, engineering and other research purposes, but artistic experimentation began to make its appearance by the mid-1960s – most notably by Dr. Thomas Calvert. By the mid-1970s, many such efforts were beginning to enter into public media. Much computer graphics at this time involved 2-D imagery, though increasingly as computer power improved, efforts to achieve 3-D realism became the emphasis. By the late 1980s, photo-realistic 3-D was beginning to appear in film movies, and by mid-1990s had developed to the point where 3-D animation could be used for entire feature film production.
The special effects of the 1990 action film Total Recall were developed by visual-effects company Dream Quest Images, with contributions by Stetson Visual Services, Metrolight Studios, and Industrial Light & Magic. Over 100 visual effects were produced for the film, which relied almost entirely on practical effects at a time when computer-generated imagery was a new and rarely-used technique.
The special effects of the 1991 American science fiction action film Terminator 2: Judgment Day were developed by four core groups: Industrial Light & Magic (ILM), Stan Winston Studio, Fantasy II Film Effects, and 4-Ward Productions. Pacific Data Images and Video Images provided some additional effects.
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