Motion Pictures - The Invention Of Motion Pictures, Sound Joins The Image, Color Comes To Film, Later Film History - Equipment
cameras camera shutter eye
Motion pictures, also called film, cinema or movies, are a series of images, recorded on strips of film, that create the illusion of continuous motion. A series of rapidly shown images appear to move because of a phenomena called the persistence of vision. The eye does not react instantly to changes in its field of vision. In fact, the eye continues to "see" an image for 1/10-1/20 of a second after it changes. So if a sequence of images can be shown at a rate of approximately 20 per second, it will appear as continuous motion to the eye. That is just what happens in a motion picture.
Camera
In photography the exposure of film can be controlled by changing the amount of light entering the lens, or the amount of time the shutter remains open. The shutter speed in a motion picture camera is controlled by the fact that 24 frames must be shot per second. No exposure can be longer than 1/24th of a second. Motion picture cameras use a shutter that looks like a rotating propeller with two blades. The propeller can be made wider to decrease the percentage of time the lens is open, and thereby shorten exposures.
The pull-down mechanism, invented at the end of the nineteenth century, moves the film through the camera, holds it still in position for 1/24th of a second while the exposure is made, then moves the film to the next frame. It does this in perfect synchronization with the revolving shutter that exposes the film.
Early motion picture cameras were large and heavy. But by the mid-1950s, technology developed during World War II lead to smaller, lighter cameras that even allowed cinematographers to hold the smallest cameras. This freed the cameras from a tripod, allowing for more innovative camera work. For moving camera effects, cameras can be put on platforms that are attached to rubber wheels or steel rails like railroad tracks. They can also be raised and lowered on cranes.
Additional Topics
Many of the principles behind motion pictures were understood well before the invention of "the movies." In 1832, Simon Ritter von Stampfer of Vienna created the stroboscope. Images spinning on a disc were viewed through slits in a second disc. This displayed the images sequentially at a fast enough rate to simulate a couple seconds worth of motion. A primitive kind of slide projecto…
The ability to reproduce sound already existed in phonographs. Many tried unsuccessfully to link them to films. A workable system to join sound and motion pictures proved complex, and required a great deal of research money. American Telephone and Telegraph, the largest corporation in the U.S., worked on the problem through its Western Electric branch. A 1924 sound-on-a-disc system was at first re…
In the 1920s and 1930s, motion pictures became a big business in the U.S., and most were produced like products on an assembly line. Often, Hollywood films did not have distinct personalities. They instead fit into genre types: western, musical, horror, gangster, and comedy. Exceptions, like Orson Welles' Citizen Kane (1941), were rare. In Europe, motion pictures remained a smaller scale bu…
At the end of the process, every motion picture goes through a projector. From the advent of sound until the mid-1970s projectors changed little. The system a projector uses for moving the film is similar to that used by a motion picture camera. A pull-down mechanism moves the film through the projector, while a rotating shutter only emits light while a frame is in position. The primary problem in…
Motion picture production has three primary stages: pre-production, production, and post-production. Preproduction gets underway when financing is secured. It involves finishing a script, finalizing the cast and crew, deciding on how various shots will tell the story of the film, and figuring out locations. A detailed budget is created. Good pre-production work saves a great deal of time and money…
The final phase of making a motion picture, post-production, begins after the film footage has been shot, and results in the finished product. Post-production consists of editing, sound mixing, and special effects. Editing is the process of putting camera shots together in a way that tells the story in an interesting manner. A camera shot is a piece of continuously shot film without a break in the…
Special effects have always been one of the chief attractions of motion pictures. Special effects are generally created through animation, miniatures, or matte shots. Animation is any process whereby frames are shot individually. This can range from cartoons to sequences in which objects appear to move because the camera was stopped, the object was moved a little, and then another frame was taken.…
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