In optics, an aperture is a hole or an opening through which light travels. More the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An optical system has many openings or structures that limit the ray bundles; these structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, the aperture stop is the stop that determines the ray cone angle and brightness at the image point. In some contexts in photography and astronomy, aperture refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope, the aperture stop is the edges of the objective lens or mirror. One speaks of a telescope as having, for example, a 100-centimeter aperture. Note that the aperture stop is not the smallest stop in the system.
Magnification and demagnification by lenses and other elements can cause a large stop to be the aperture stop for the system. In astrophotography, the aperture may be given as a linear measure or as the dimensionless ratio between that measure and the focal length. In other photography, it is given as a ratio. Sometimes stops and diaphragms are called apertures when they are not the aperture stop of the system; the word aperture is used in other contexts to indicate a system which blocks off light outside a certain region. In astronomy, for example, a photometric aperture around a star corresponds to a circular window around the image of a star within which the light intensity is assumed; the aperture stop is an important element in most optical designs. Its most obvious feature is; this can be either unavoidable, as in a telescope where one wants to collect as much light as possible. In both cases, the size of the aperture stop is constrained by things other than the amount of light admitted. Smaller stops produce a longer depth of field, allowing objects at a wide range of distances to all be in focus at the same time.
The stop limits the effect of optical aberrations. If the stop is too large, the image will be distorted. More sophisticated optical system designs can mitigate the effect of aberrations, allowing a larger stop and therefore greater light collecting ability; the stop determines. Larger stops can cause the intensity reaching the film or detector to fall off toward the edges of the picture when, for off-axis points, a different stop becomes the aperture stop by virtue of cutting off more light than did the stop, the aperture stop on the optic axis. A larger aperture stop requires larger diameter optics, which are more expensive. In addition to an aperture stop, a photographic lens may have one or more field stops, which limit the system's field of view; when the field of view is limited by a field stop in the lens vignetting results. The biological pupil of the eye is its aperture in optics nomenclature. Refraction in the cornea causes the effective aperture to differ from the physical pupil diameter.
The entrance pupil is about 4 mm in diameter, although it can range from 2 mm in a brightly lit place to 8 mm in the dark. In astronomy, the diameter of the aperture stop is a critical parameter in the design of a telescope. One would want the aperture to be as large as possible, to collect the maximum amount of light from the distant objects being imaged; the size of the aperture is limited, however, in practice by considerations of cost and weight, as well as prevention of aberrations. Apertures are used in laser energy control, close aperture z-scan technique, diffractions/patterns, beam cleaning. Laser applications include Q-switching, high intensity x-ray control. In light microscopy, the word aperture may be used with reference to either the condenser, field iris or objective lens. See Optical microscope; the aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor. In combination with variation of shutter speed, the aperture size will regulate the film's or image sensor's degree of exposure to light.
A fast shutter will require a larger aperture to ensure sufficient light exposure, a slow shutter will require a smaller aperture to avoid excessive exposure. A device called a diaphragm serves as the aperture stop, controls the aperture; the diaphragm functions much like the iris of the eye – it controls the effective diameter of the lens opening. Reducing the aperture size increases the depth of field, which describes the extent to which subject matter lying closer than or farther from the actual plane of focus appears to be in focus. In general, the smaller the aperture, the greater the distance from the plane of focus the subject matter may be while
A three-dimensional stereoscopic film is a motion picture that enhances the illusion of depth perception, hence adding a third dimension. The most common approach to the production of 3D films is derived from stereoscopic photography. In this approach, a regular motion picture camera system is used to record the images as seen from two perspectives, special projection hardware or eyewear is used to limit the visibility of each image to the viewer's left or right eye only. 3D films are not limited to theatrical releases. 3D films have existed in some form since 1915, but had been relegated to a niche in the motion picture industry because of the costly hardware and processes required to produce and display a 3D film, the lack of a standardized format for all segments of the entertainment business. Nonetheless, 3D films were prominently featured in the 1950s in American cinema, experienced a worldwide resurgence in the 1980s and 1990s driven by IMAX high-end theaters and Disney-themed venues.
3D films became successful throughout the 2000s, peaking with the success of 3D presentations of Avatar in December 2009, after which 3D films again decreased in popularity. Certain directors have taken more experimental approaches to 3D filmmaking, most notably celebrated auteur Jean-Luc Godard in his films 3x3D and Goodbye to Language; the stereoscopic era of motion pictures began in the late 1890s when British film pioneer William Friese-Greene filed a patent for a 3D film process. In his patent, two films were projected side by side on screen; the viewer looked through a stereoscope to converge the two images. Because of the obtrusive mechanics behind this method, theatrical use was not practical. Frederic Eugene Ives patented his stereo camera rig in 1900; the camera had two lenses coupled together 13⁄4 inches apart. On June 10, 1915, Edwin S. Porter and William E. Waddell presented tests to an audience at the Astor Theater in New York City. In red-green anaglyph, the audience was presented three reels of tests, which included rural scenes, test shots of Marie Doro, a segment of John Mason playing a number of passages from Jim the Penman, Oriental dancers, a reel of footage of Niagara Falls.
However, according to Adolph Zukor in his 1953 autobiography The Public Is Never Wrong: My 50 Years in the Motion Picture Industry, nothing was produced in this process after these tests. The earliest confirmed 3D film shown to an out-of-house audience was The Power of Love, which premiered at the Ambassador Hotel Theater in Los Angeles on 27 September 1922; the camera rig was a product of the film's producer, Harry K. Fairall, cinematographer Robert F. Elder, it was filmed dual-strip in black and white, single strip color analglyphic release prints were produced using a color film invented and patented by Harry K. Fairall. A single projector could be used to display the movie but anaglyph glasses were used for viewing; the camera system and special color release print film all received U. S Patent No. 1,784,515 on Dec 9, 1930. After a preview for exhibitors and press in New York City, the film dropped out of sight not booked by exhibitors, is now considered lost. Early in December 1922, William Van Doren Kelley, inventor of the Prizma color system, cashed in on the growing interest in 3D films started by Fairall's demonstration and shot footage with a camera system of his own design.
Kelley struck a deal with Samuel "Roxy" Rothafel to premiere the first in his series of "Plasticon" shorts entitled Movies of the Future at the Rivoli Theater in New York City. In December 1922, Laurens Hammond premiered his Teleview system, shown to the trade and press in October. Teleview was the first alternating-frame 3D system seen by the public. Using left-eye and right-eye prints and two interlocked projectors and right frames were alternately projected, each pair being shown three times to suppress flicker. Viewing devices attached to the armrests of the theater seats had rotary shutters that operated synchronously with the projector shutters, producing a clean and clear stereoscopic result; the only theater known to have installed Teleview was the Selwyn Theater in New York City, only one show was presented with it: a group of short films, an exhibition of live 3D shadows, M. A. R. S; the only Teleview feature. The show ran for several weeks doing good business as a novelty, but Teleview was never seen again.
In 1922, Frederic Eugene Ives and Jacob Leventhal began releasing their first stereoscopic shorts made over a three-year period. The first film, entitled Plastigrams, was distributed nationally by Educational Pictures in the red-and-blue anaglyph format. Ives and Leventhal went on to produce the following stereoscopic shorts in the "Stereoscopiks Series" released by Pathé Films in 1925: Zowie, Luna-cy!, The Run-Away Taxi and Ouch. On 22 September 1924, Luna-cy! was re-released in the DeForest Phonofilm sound-on-film system. The late 1920s to early 1930s saw little interest in stereoscopic pictures. In Paris, Louis Lumiere shot footage with his stereoscopic camera in September 1933; the following March he exhibited a remake of his 1895 short film L'Arrivée du Train, this time in anaglyphic 3D, at a meeting of the French Academy of Science. In 1936, Leventhal and John Norling were hired based on the
Dubbing, mixing, or re-recording is a post-production process used in filmmaking and video production in which additional or supplementary recordings are "mixed" with original production sound to create the finished soundtrack. The process takes place on a dub stage. After sound editors edit and prepare all the necessary tracks – dialogue, automated dialogue replacement, Foley, music – the dubbing mixers proceed to balance all of the elements and record the finished soundtrack. Dubbing is sometimes confused with ADR known as "additional dialogue replacement", "automated dialogue recording" and "looping", in which the original actors re-record and synchronize audio segments. Outside the film industry, the term "dubbing" refers to the replacement of the actor's voices with those of different performers speaking another language, called "revoicing" in the film industry. In the past, dubbing was practiced in musicals when the actor had an unsatisfactory singing voice. Today, dubbing enables the screening of audiovisual material to a mass audience in countries where viewers do not speak the same language as the performers in the original production.
Films and sometimes video games are dubbed into the local language of a foreign market. In foreign distribution, dubbing is common in theatrically released films, television films, television series and anime. Automated Dialog Replacement is the process of re-recording dialogue by the original actor after the filming process to improve audio quality or reflect dialogue changes. In India the process is known as "dubbing", while in the UK, it is called "post-synchronisation" or "post-sync"; the insertion of voice actor performances for animation, such as computer generated imagery or animated cartoons, is referred to as ADR although it does not replace existing dialogue. The ADR process may be used to: remove extraneous sounds such as production equipment noise, wind, or other undesirable sounds from the environment. Replace foul language for TV broadcasts of the movie. In conventional film production, a production sound mixer records dialogue during filming. During post-production, a supervising sound editor, or ADR supervisor, reviews all of the dialogue in the film and decides which lines must be re-recorded.
ADR is recorded during an ADR session. The actor the original actor from the set, views the scene with the original sound attempts to recreate the performance. Over the course of multiple takes, the actor performs the lines while watching the scene; the ADR process does not always take place in a post-production studio. The process may be recorded with mobile equipment. ADR can be recorded without showing the actor the image they must match, but by having them listen to the performance, since some actors believe that watching themselves act can degrade subsequent performances. Sometimes, a different actor than the original actor on set is used during ADR. One famous example is the Star Wars character Darth Vader portrayed by David Prowse. Other examples include: Ray Park, who acted as Darth Maul from Star Wars: Episode I – The Phantom Menace had his voice dubbed over by Peter Serafinowicz Frenchmen Philippe Noiret and Jacques Perrin, who were dubbed into Italian for Cinema Paradiso Austrian bodybuilder Arnold Schwarzenegger, dubbed for Hercules in New York Argentine boxer Carlos Monzón, dubbed by a professional actor for the lead in the drama La Mary Gert Frobe, who played Auric Goldfinger in the James Bond film Goldfinger, dubbed by Michael Collins Andie MacDowell's Jane, in Greystoke: The Legend of Tarzan, Lord of the Apes, dubbed by Glenn Close Tom Hardy, who portrayed Bane in The Dark Knight Rises, re-dubbed half of his own lines for ease of viewer comprehension Harvey Keitel was dubbed by Roy Dotrice in post production for Saturn 3 Dave Coulier dubbed replacement of swear words for Richard Pryor in multiple TV versions of his movies An alternative method to dubbing, called "rythmo band", has been used in Canada and France.
It provides a more precise guide for the actors and technicians, can be used to complement the traditional ADR method. The "band" is a clear 35 mm film leader on which the dialogue is hand-written in India ink, together with numerous additional indications for the actor—including laughs, length of syllables, mouth sounds and mouth openings and closings; the rythmo band is projected in scrolls in perfect synchronization with the picture. Studio time is used more efficiently, since with the aid of scrolling text and audio cues, actors can read more lines per hour than with ADR alone. With ADR, actors can average 10–12 lines per hour, while rythmo band can facilitate the reading of 35-50 lines per hour. However, the preparation of a rythmo band is a time-consuming process involving a series of specialists organized in a production line; this has prevented the technique from being more adopted, but software emulations of rythmo band technology overcome the dis
A film called a movie, motion picture, moving picture, or photoplay, is a series of still images that, when shown on a screen, create the illusion of moving images. This optical illusion causes the audience to perceive continuous motion between separate objects viewed in rapid succession; the process of filmmaking is both an industry. A film is created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, other visual effects; the word "cinema", short for cinematography, is used to refer to filmmaking and the film industry, to the art of filmmaking itself. The contemporary definition of cinema is the art of simulating experiences to communicate ideas, perceptions, beauty or atmosphere by the means of recorded or programmed moving images along with other sensory stimulations. Films were recorded onto plastic film through a photochemical process and shown through a movie projector onto a large screen.
Contemporary films are now fully digital through the entire process of production and exhibition, while films recorded in a photochemical form traditionally included an analogous optical soundtrack. Films are cultural artifacts created by specific cultures, they reflect those cultures. Film is considered to be an important art form, a source of popular entertainment, a powerful medium for educating—or indoctrinating—citizens; the visual basis of film gives it a universal power of communication. Some films have become popular worldwide attractions through the use of dubbing or subtitles to translate the dialog into other languages; the individual images that make up a film are called frames. In the projection of traditional celluloid films, a rotating shutter causes intervals of darkness as each frame, in turn, is moved into position to be projected, but the viewer does not notice the interruptions because of an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after its source disappears.
The perception of motion is due to a psychological effect called the phi phenomenon. The name "film" originates from the fact that photographic film has been the medium for recording and displaying motion pictures. Many other terms exist for an individual motion-picture, including picture, picture show, moving picture and flick; the most common term in the United States is movie. Common terms for the field in general include the big screen, the silver screen, the movies, cinema. In early years, the word sheet was sometimes used instead of screen. Preceding film in origin by thousands of years, early plays and dances had elements common to film: scripts, costumes, direction, audiences and scores. Much terminology used in film theory and criticism apply, such as mise en scène. Owing to the lack of any technology for doing so, the moving images and sounds could not be recorded for replaying as with film; the magic lantern created by Christiaan Huygens in the 1650s, could be used to project animation, achieved by various types of mechanical slides.
Two glass slides, one with the stationary part of the picture and the other with the part, to move, would be placed one on top of the other and projected together the moving slide would be hand-operated, either directly or by means of a lever or other mechanism. Chromotrope slides, which produced eye-dazzling displays of continuously cycling abstract geometrical patterns and colors, were operated by means of a small crank and pulley wheel that rotated a glass disc. In the mid-19th century, inventions such as Joseph Plateau's phenakistoscope and the zoetrope demonstrated that a designed sequence of drawings, showing phases of the changing appearance of objects in motion, would appear to show the objects moving if they were displayed one after the other at a sufficiently rapid rate; these devices relied on the phenomenon of persistence of vision to make the display appear continuous though the observer's view was blocked as each drawing rotated into the location where its predecessor had just been glimpsed.
Each sequence was limited to a small number of drawings twelve, so it could only show endlessly repeating cyclical motions. By the late 1880s, the last major device of this type, the praxinoscope, had been elaborated into a form that employed a long coiled band containing hundreds of images painted on glass and used the elements of a magic lantern to project them onto a screen; the use of sequences of photographs in such devices was limited to a few experiments with subjects photographed in a series of poses because the available emulsions were not sensitive enough to allow the short exposures needed to photograph subjects that were moving. The sensitivity was improved and in the late 1870s, Eadweard Muybridge created the first animated image sequences photographed in real-time. A row of cameras was used, each, in turn, capturing one image on a photographic glass plate, so the total number of images in each sequence was limited by the number of cameras, about two dozen at most. Muybridge used his system to analyze the movements of a wi
Aerial perspective or atmospheric perspective refers to the effect the atmosphere has on the appearance of an object as it is viewed from a distance. As the distance between an object and a viewer increases, the contrast between the object and its background decreases, the contrast of any markings or details within the object decreases; the colours of the object become less saturated and shift towards the background colour, blue, but under some conditions may be some other colour. Aerial perspective was used in paintings from the Netherlands in the 15th century, explanations of its effects were with varying degrees of accuracy written by polymaths such as Leon Battista Alberti and Leonardo da Vinci; the latter used aerial perspective in many of his paintings such as the Mona Lisa and The Last Supper. Atmospheric perspective was used in Pompeian Second Style paintings, one of the Pompeian Styles, dating as early as 30 BCE. A notable example is the Gardenscape from the Villa of Livia in Italy.
The major component affecting the appearance of objects during daylight is scattering of light, called skylight, into the line of sight of the viewer. Scattering occurs from molecules of the air and from larger particles in the atmosphere such as water vapour and smoke. Scattering adds the sky light as a veiling luminance onto the light from the object, reducing its contrast with the background sky light. Skylight contains more light of short wavelength than other wavelengths, why distant objects appear bluish. A minor component is scattering of light out of the line of sight of the viewer. Under daylight, this either opposes it. At night there is no skylight, so scattering out of the line of sight becomes the major component affecting the appearance of self-luminous objects; such objects have their contrasts reduced with the dark background, their colours are shifted towards red. The ability of a person with normal visual acuity to see fine details is determined by his or her contrast sensitivity.
Contrast sensitivity is the reciprocal of the smallest contrast for which a person can see a sine-wave grating. A person's contrast sensitivity function is contrast sensitivity as a function of spatial frequency. Peak contrast sensitivity is at about 4 cycles per degree of visual angle. At higher spatial frequencies, comprising finer and finer lines, contrast sensitivity decreases, until at about 40 cycles per degree the brightest of bright lines and the darkest of dark lines cannot be seen; the high spatial frequencies in an image give it its fine details. Reducing the contrast of an image reduces the visibility of these high spatial frequencies because contrast sensitivity for them is poor; this is. It is important to emphasize. Blurring is accomplished by reducing the contrast only of the high spatial frequencies. Aerial perspective reduces the contrast of all spatial frequencies. In art painting, aerial perspective refers to the technique of creating an illusion of depth by depicting distant objects as paler, less detailed, bluer than near objects.
Aerial landscape art Aerial shot Haze Landscape art Rayleigh scattering Tyndall effect
A bird's-eye view is an elevated view of an object from above, with a perspective as though the observer were a bird used in the making of blueprints, floor plans, maps. It can be an aerial photograph, but a drawing. Before manned flight was common, the term "bird's eye" was used to distinguish views drawn from direct observation at high locations, from those constructed from an imagined perspectives. Bird's eye views; the last great flourishing of them was in the mid-to-late 19th century, when bird's eye view prints were popular in the United States and Europe. The terms aerial view and aerial viewpoint are sometimes used synonymous with bird's-eye view; the term aerial view can refer to any view from a great height at a wide angle, as for example when looking sideways from an airplane window or from a mountain top. Overhead view is synonymous with bird's-eye view but tends to imply a less lofty vantage point than the latter term. For example, in computer and video games, an "overhead view" of a character or situation places the vantage point only a few feet above human height.
See top-down perspective. Recent technological and networking developments have made satellite images more accessible. Microsoft Bing Maps offers direct overhead satellite photos of the entire planet but offers a feature named Bird's eye view in some locations; the Bird's Eye photos are angled at 40 degrees rather than being straight down. Satellite imaging programs and photos have been described as offering a viewer the opportunity to "fly over" and observe the world from this specific angle. In filmmaking and video production, a bird's-eye shot refers to a shot looking directly down on the subject; the perspective is foreshortened, making the subject appear short and squat. This shot can be used to give an overall establishing shot of a scene, or to emphasise the smallness or insignificance of the subjects; these shots are used for battle scenes or establishing where the character is. It is shot by lifting the camera up by hands or by hanging it off something strong enough to support it; when a scene needs a large area shot, it is a crane shot.
A distinction is sometimes drawn between a bird's-eye view and a bird's-flight view, or "view-plan in isometrical projection". Whereas a bird's-eye view shows a scene from a single viewpoint in true perspective, for example, the foreshortening of more distant features, a bird's-flight view combines a vertical plan of ground-level features with perspective views of buildings and other standing features, all presented at the same scale; the landscape appears "as it would unfold itself to any one passing over it, as in a balloon, at a height sufficient to abolish sharpness of perspective, yet low enough to allow of distinct view of the scene beneath". The technique was popular among local surveyors and cartographers of the sixteenth and early seventeenth centuries. Aerial landscape art Aerial perspective Aerial photography Camera angle Cinematic techniques Filmmaking Google Earth Pictorial map Pictometry Plans Top-down perspective Video production Worm's-eye view
In film making, the 180-degree rule is a basic guideline regarding the on-screen spatial relationship between a character and another character or object within a scene. By keeping the camera on one side of an imaginary axis between two characters, the first character is always frame right of the second character. Moving the camera over the axis is called jumping the line or crossing the line; the 180-degree rule enables the audience to visually connect with unseen movement happening around and behind the immediate subject and is important in the narration of battle scenes. In a dialogue scene between two characters, a straight line can be imagined running between the two characters, extending to infinity. If the camera remains on one side of this line, the spatial relationship between the two characters will be consistent from shot to shot if one of the characters is not on screen. Shifting to the other side of the characters on a cut will reverse the order of the characters from left to right and may disorient the audience.
The rule applies to the movement of a character as the "line" created by the path of the character. For example, if a character is walking in a leftward direction and is to be picked up by another camera, the character must exit the first shot on frame left and enter the next shot frame right. A jump cut can be used to denote time. If a character leaves the frame on the left side and enters the frame on the left in a different location, it can give the illusion of an extended amount of time passing. Another example could be a car chase: If a vehicle leaves the right side of the frame in one shot, it should enter from the left side of the frame in the next shot. Leaving from the right and entering from the right creates a similar sense of disorientation as in the dialogue example; the imaginary line allows viewers to orient themselves with the position and direction of action in a scene. If a shot following an earlier shot in a sequence is located on the opposite side of the 180-degree line it is called a "reverse cut".
Reverse cuts disorient the viewer by presenting an opposing viewpoint of the action in a scene and altering the perspective of the action and the spatial orientation established in the original shot. There are a variety of ways to avoid confusion related to crossing the line due to particular situations caused by actions or situations in a scene that would necessitate breaking the 180-degree line; the movement in the scene can be altered, or cameras set up on one side of the scene so that all the shots reflect the view from that side of the 180-degree line. Another way to allow for crossing the line is to have several shots with the camera arching from one side of the line to the other during the scene; that shot can be used to orient the audience to the fact that they are looking at the scene from another angle. In the case of movement, if a character is seen walking into frame from behind on the left side walking towards a building corner on the right, as they walk around the corner of the building, the camera can catch them coming towards the camera on the other side of the building entering the frame from the left side and walk straight at the camera and exit the left side of the frame.
To minimize the "jolt" between shots in a sequence on either sides of the 180-degree line, a buffer shot can be included along the 180-degree line separating each side. This lets. In professional productions, the applied 180-degree rule is an essential element for a style of film editing called continuity editing; the rule is not always obeyed. Sometimes a filmmaker purposely breaks the line of action to create disorientation. Carl Theodor Dreyer did this in The Passion of Joan of Arc; the Wachowskis and directors Jacques Demy, Tinto Brass, Yasujirō Ozu, Wong Kar-wai, Jacques Tati sometimes ignored this rule as has Lars von Trier in Antichrist. In the seminal film of the French New Wave, À bout de souffle, Jean-Luc Godard breaks the rule in the first five minutes in a car scene that jumps between the front and back seats, improvising an "aesthetic rebellion" for which the New Wave would become known; when the rule is broken accidentally, or for a technical reason, there are ways for the editor to attempt to hide the mistake.
The editor may pre-lap one or two words of dialog before the cut, so that the viewer is concentrating on what is being said and may be less to notice the rule-breaking cut. Some styles used with the 180-degree rule can create a visual rhythm. By moving the camera closer to the axis for a close-up shot, it can intensify a scene when paired with a long shot; when the camera is moved further away from the axis for a long shot after a close-up shot, it may provide a break in the action of the scene. In the Japanese animated picture Paprika, two of the main characters discuss crossing the line and demonstrate the disorienting effect of performing the action. Continuity editing 30-degree rule "The 180-degree rule" and "Breaking the 180-degree rule", two articles explaining the 180-degree rule in depth; some excerpts on the 30 Degree rule as well. VIDEO on 180 degree rule