Cameras work with the light of the visible spectrum or with other portions of the electromagnetic spectrum.
A still camera is an optical device which creates a single image of an object or scene, and records it on an electronic sensor or photographic film. All cameras use the same basic design: light enters an enclosed box through a converging lens/convex lens and an image is recorded on a light-sensitive medium(mainly a transition metal-hallide).
A shutter mechanism controls the length of time that light can enter the camera. Most photographic cameras have functions that allow a person to view the scene to be recorded, allow for a desired part of the scene to be in focus, and to control the exposure so that it is not too bright or too dim.
The forerunner to the photographic camera was the camera obscura. In the fifth century B.C., the Chinese philosopher Mo Ti noted that a pinhole can form an inverted and focused image, when light passes through the hole and into a dark area. Mo Ti is the first recorded person to have exploited this phenomenon to trace the inverted image to create a picture.
The Italian scientist Giambattista della Porta described the camera obscura in detail in his 1558 work Magia Naturalis, and specifically suggested that an artist could project a camera obscura’s images onto paper, and trace the outlines. The camera obscura was popular as an aid for drawing and painting from the 1600s to the 1800s.