A camera is a device used to capture images, either as still photographs or as sequences of moving images (movies or videos). The term comes from the camera obscura (Latin for "dark chamber"), an early mechanism of projecting images where an entire room functioned as a real-time imaging system; the modern camera evolved from the camera obscura.

Cameras may work with the light of the visible spectrum or with other portions of the electromagnetic spectrum. A camera generally consists of an enclosed hollow with an opening (aperture) at one end for light to enter, and a recording or viewing surface for capturing the light at the other end. A majority of cameras have a lens positioned in front of the camera's opening to gather the incoming light and focus all or part of the image on the recording surface. The diameter of the aperture is often controlled by a diaphragm mechanism, but some cameras have a fixed-size aperture.

History

Main article: History of the camera

Camera obscura.

The forerunner to the camera was the camera obscura. The camera obscura is an instrument consisting of a darkened chamber or box, into which light is admitted through a convex lens, forming an image of external objects on a surface of paper or glass, etc., placed at the focus of the lens.^[1] The camera obscura was first invented by the Iraqi scientist Ibn al-Haytham (Alhazen) as described in his Book of Optics (1015-1021).^[2] Irish scientist Robert Boyle and his assistant Robert Hooke later developed a portable camera obscura in the 1660s.^[3]

The first camera that was small and portable enough to be practical for photography was built by Johann Zahn in 1685, though it would be almost 150 years before technology caught up to the point where this was practical. Early photographic cameras were essentially similar to Zahn's model, though usually with the addition of sliding boxes for focusing. Before each exposure, a sensitized plate would be inserted in front of the viewing screen to record the image. Jacques Daguerre's popular daguerreotype process utilized copper plates, while the calotype process invented by William Fox Talbot recorded images on paper.

The first permanent colour photograph, taken by James Clerk Maxwell in 1861.

The first permanent photograph was made in 1826 by Joseph Nicéphore Niépce using a sliding wooden box camera made by Charles and Vincent Chevalier in Paris. Niépce built on a discovery by Johann Heinrich Schultz (1724): a silver and chalk mixture darkens under exposure to light. However, while this was the birth of photography, the camera itself can be traced back much further. Before the invention of photography, there was no way to preserve the images produced by these cameras apart from manually tracing them.

The development of the collodion wet plate process by Frederick Scott Archer in 1850 cut exposure times dramatically, but required photographers to prepare and develop their glass plates on the spot, usually in a mobile darkroom. Despite their complexity, the wet-plate ambrotype and tintype processes were in widespread use in the latter half of the 19th century. Wet plate cameras were little different from previous designs, though there were some models, such as the sophisticated Dubroni of 1864, where the sensitizing and developing of the plates could be carried out inside the camera itself rather than in a separate darkroom. Other cameras were fitted with multiple lenses for making cartes de visite. It was during the wet plate era that the use of bellows for focusing became widespread.

The first colour photograph was made by Scottish physicist James Clerk Maxwell, with the help of English inventor and photographer Thomas Sutton, in 1861^[4]