Camera Obscura: Another optical copying device which is much larger than the lucida. It relies on the principle that rays of light will pass through a small lens in the side of a darkened cabinet and then be projected either straight or by reflection from a mirror on to a piece of paper. The principle was first noted by Aristotle. Early astronomers found it helpful to use an obscura to observe the stars; it is described in this connection by the Arabian Alhazen at the beginning of the 11th century. The artist's obscura was probably first constructed by Leone Battista Alberti (1404-72). Giovanni Battista della Porta is likely to have been the first to make a written account of its use for drawing, in his Magia Naturalis (1558).

 

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Camera Obscura: A darkened chamber with a hole in one wall through which light enters, creating an image of the outdoors on the opposite wall. It was the earliest form of a 'camera,' and is where the name derives.

Partial Obscuration: Denotes that 1/8th or more of the sky, but not all of the sky, is hidden by any surface-based phenomena in the atmosphere, excluding precipitation. It often reduces horizontal visibility but . . . View Full Definition

Pinhole Camera: Camera without a lens which uses a very small hole pierced in one end to allow light to pass through and form an image on the back of the camera which can be covered by film.

Plate Camera: Camera designed to take glass plates but often adapted to take cut film.