The camera obscura (Latin; camera for "vaulted chamber/room", obscura for "dark", together "darkened chamber/room"; plural: camera obscuras or camerae obscurae) is an optical device that projects an image of its surroundings on a screen. It is used in drawing and for entertainment, and was one of the inventions that led to photography and the camera. The device consists of a box or room with a hole in one side. Light from an external scene passes through the hole and strikes a surface inside where it is reproduced, upside-down, but with color and perspective preserved. The image can be projected onto paper, and can then be traced to produce a highly accurate representation.
Using mirrors, as in the 18th century overhead version (illustrated in the History section below), it is possible to project a right-side-up image. Another more portable type is a box with an angled mirror projecting onto tracing paper placed on the glass top, the image being upright as viewed from the back.
As a pinhole is made smaller, the image gets sharper, but the projected image becomes dimmer. With too small a pinhole, however, the sharpness worsens, due to diffraction. Some practical camera obscuras use a lens rather than a pinhole because it allows a larger aperture, giving a usable brightness while maintaining focus. (See pinhole camera for construction information.)
Famous quotes containing the word camera:
“If I were just curious, it would be very hard to say to someone, “I want to come to your house and have you talk to me and tell me the story of your life.” I mean people are going to say, “You’re crazy.” Plus they’re going to keep mighty guarded. But the camera is a kind of license. A lot of people, they want to be paid that much attention and that’s a reasonable kind of attention to be paid.”
—Diane Arbus (1923–1971)