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Time-lapse photography is a Cinematography technique whereby each Film frame is captured at a rate much slower than it will be played back. When replayed at normal speed, time appears to be moving faster and thus lapsing. Processes that would normally appear subtle to the human eye, such as motion in the sky, become very pronounced. Time-lapse is the extreme version of the cinematography technique of '''undercranking'''. Time-lapse photography of biologic phenomena was partially pioneered by Roman Vishniac from 1915 to 1918. Some classic subjects of timelapse photography include:
The technique has also been used to photograph crowds, traffic, and even television. The effect of photographing a subject that changes imperceptibly slowly, is to create a smooth impression of motion. A subject that is changing quickly already is transformed into an onslaught of activity. The first use of time-lapse photography in a feature film was in Georges Méliès ' motion picture ''Carrefour De L'Opera'' ( 1897 ). Time-lapse photography was further pioneered in a series of feature films called ''Bergfilms'' ( Mountain Film s) by Arnold Fanck , in the 1920s , including ''The Holy Mountain'' ( 1926 ). But no filmmaker can be credited for popularizing time-lapse more than John Ott . His cinematography of flowers blooming in such classic documentaries as Walt Disney's ''Secrets of Life'' ( 1956 ), pioneered the modern use of time-lapse on film and television. The first major usage of time lapse in a feature film was '' Koyaanisqatsi '' ( 1983 ). The non-narrative film was composed almost entirely from time-lapse of clouds, crowds, and cities lensed by cinematographer Ron Fricke . Countless other films, commercials, TV shows and presentations have included time-lapse. For example, Peter Greenaway 's film '' A Zed & Two Noughts '' featured a sub-plot involving time-lapse photography of decomposing animals and included a composition called "Time-lapse" written for the film by Michael Nyman . More recently, Adam Zoghlin's time-lapse cinematography was featured in the CBS television series '' Early Edition '', depicting the adventures of a character that receives tomorrow's newspaper today. Mild forms of timelapse are referred to as fast motion or '''fast forward'''. This type of timelapse resembles a VCR in fast forward mode. For example, a man riding a bicycle will display legs pumping furiously while he flashes through city streets at the speed of a racing car. When used in motion pictures and on television it can serve one of several purposes. One popular usage is for comic effect. For example, a slapstick style comic scene might be played in fast motion with accompanying music. Another use of fast motion is to speed up slow segments of a TV program that would otherwise take up to much of the time allotted a TV show. This allows, for example, on slow scene in house redecorating show of furniture being moved around or replaced to be compressed in a smaller allotment of time while still allowing the viewer to see what took place. The opposite of fast motion is slow motion. Cinematographers refer to fast motion as undercranking since it was originally achieved by cranking a handcranked camera slower than normal. HOW TIMELAPSE WORKS Film is normally projected at 24 Frame/s . Meaning that 24 images appear on the screen every second. Under normal circumstances a film ''camera'' will record images at 24 frame/s. Since the projection speed and the recording speed are the same the images onscreen appear to move normally. Even if the film camera is set to record at a slower speed, it will still be projected at 24 frame/s. Thus the image on screen will appear to move faster. The change in speed of the onscreen image can be calculated by simply dividing the projection speed by the camera speed. So for example, a film that is recorded at 12 frames per second will appear to move twice as fast. Shooting at camera speeds between 8 and 24 frame/s is usually referred to as undercranking. Shooting at slower speeds is referred to as time-lapse. The same principles apply to video and other digital photography techniques, however most video cameras do not have variable frame speeds. Time-lapse can be achieved with normal movie cameras, though often the camera must be modified with a device called an Intervalometer . The intervalometer regulates the motion of the camera according to a specific interval of time between frames. SHORT EXPOSURE VS. LONG EXPOSURE TIME-LAPSE In addition to modifying the speed of the camera it is also important to consider the relationship between the frame interval and the '''exposure time'''. This relationship essentially controls the amount of Motion Blur present in each frame and it is, in principle, exactly the same as adjusting the Shutter Angle on a movie camera. A film camera normally records film at twenty four frames per second. During each 24th of a second the film is actually exposed to light for roughly half the time. The rest of the time it is hidden behind the shutter. Thus exposure time for motion picture film is normally calculated to be one 48th of a second (1/48 second, often rounded to 1/50 second). Adjusting the shutter angle on a film camera can add or reduce the amount of motion blur by changing the amount of time that the film frame is actually exposed to light. In time-lapse photography the camera records images at a specific slow interval such as one frame every thirty seconds (1/30 frame/s). The shutter will be open for some portion of that time. In short exposure time-lapse the film is exposed to light for a normal exposure time over an abnormal frame interval. So for example the camera will be set up to expose a frame for 1/50th of a second every 30 seconds. Such a setup will create the effect of an extremely tight shutter angle giving the resulting film a stop-animation or clay-mation quality. In long exposure time-lapse the exposure time will approximate the effects of a normal shutter angle. Normally this means that the exposure time should be half of the frame interval. Thus a 30 second frame interval should be accompanied by a 15 second exposure time to simulate a normal shutter. The resulting film will appear smooth. The exposure time can be calculated based on the desired shutter angle effect and the frame interval with the equation: Long exposure time-lapse is less common because it is often difficult to properly expose film at such a long period, especially in daylight situations. A film frame that is exposed for 15 seconds will receive 300 times more light than its 1/50th of a second counterpart. (Thus it will be more than 8 Stops over normal exposure.) A scientific grade Neutral Density Filter can be used to alleviate this problem. TIME-LAPSE CAMERA MOVEMENT Some of the most stunning timelapse images are created by moving the camera during the shot. A time-lapse camera can be mounted to a moving car for example to create a notion of extreme speed. However to achieve the effect of a simple Tracking Shot it is necessary to use Motion Control to move the camera. A motion control rig can be set to dolly or pan the camera at a glacially slowly pace. When the image is projected it could appear that the camera is moving at a normal speed while the world around it is in timelapse. This juxtaposition can greatly heighten the timelapse illusion. The speed that the camera must move to create a perceived normal camera motion can be calculated by inverting the time-lapse equation: Baraka was one of the first films to use this effect to its extreme. Director and Cinematographer Ron Fricke designed his own motion control rig that utilized Stepper Motor s to pan, tilt and dolly the camera. Related techniques REFERENCES
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