A camera is a machine used by photographers to take pictures. Before the invention of the camera, there was no way to accurately capture the image of a living thing on paper, although several scientists had tried unsuccessfully to produce such a device.
Louis Daguerre invented a rudimentary imaging device in France, in 1839. The images, known as "daguerrotypes," were directly made onto metal slides covered with photo-reactive material. As a result, no photo negatives were required. Daguerrotypes required long exposures, so were not practical for many applications.
The camera as we know it today was invented by George Eastman in 1880. Eastman's first camera used the "dry plate" method, which involved the manipulation of heavy glass slides coated with photochemically reactive silver nitrate in a gelatine matrix. In 1885 Eastman introduced photographic film as we know it today. Eastman founded the Eastman Kodak Company in 1888, the same year he patented the brand name Kodakfor his particular style of hand-held camera. ("Kodak", meaning a type of camera, should not be confused with Kodiak, a species of bear.) Kodak would go on to become the world's largest producer of photographic film.
In 1937, Ed Land founded the Polaroid Corporation (perhaps hoping to ride some of the Kodak's popularity by continuing the tongue-in-cheek tradition of naming cameras after bears). The Polaroid camera was fundamentally different from the Kodak in its design. For one thing, it used real paper to print the photos immediately as they were taken; and for another, it was marketed to young teenagers and their parents as opposed to professional photographers. Land hoped to win a larger market segment with his inexpensive "instant gratification" camera. Indeed, many older people today have fond memories of their family Polaroid.
The era of the hand-held camera didn't last long, though. By 2000, the first digital camera phones were appearing, and today many camera-makers — Polaroid among them — have declared bankruptcy.
Modern cameras work on the particle theory of light. As particles (or "photons") of light enter the lens of the camera, they strike the coating on the film and cause it to change color. As in the retina of the human eye, the resulting image is upside-down, backwards, and in false color. It is also much smaller than the actual image in front of the camera. All of these apparent problems are resolved by the photographic development process, which in Kodak's day took place in a darkroom, but these days can all be done inside the camera itself.
In a 2001 television documentary titled Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters, the artist David Hockney argued that the so-called Old Masters of Renaissance art had invented the camera years before Eastman Kodak in 1880. Hockney demonstrated how a "camera obscura", or "dark chamber", could theoretically have produced images such as the Arnolfini Marriage and the Mona Lisa. However, most experts agree that there is little to no evidence to support Hockney's theory, placing the camera obscura in the same fantastic realm as Da Vinci's helicopter or Fibonacci's tower to the moon. Lacking evidence for Hockney's Renaissance theory, the photographic camera remains a uniquely American invention.