Latin term meaning dark room. Optical device which may be more or less complex. Its fundamental components consist of a box with a hole and a lens through which light reflects on a screen (usually of frosted glass) placed inside the box on the opposite wall from the lens. Through the regulation of the distance between the lens and the screen, the camera obscura allows the projection of the image taken from the subject, although upside down. The camera obscura (already documented in the 15th Century and perfected by Erasmus Reinhold in 1540) finds particular use in the course of the 18th Century to help vedutisti (see veduta) reproduce a natural scene in a reduced format and in a correct perspective.