Frisius Gemma's illustration of a camera obscura, 1544.
© Science Museum / Science & Society Picture Library
Plate originally published in Reinerus Frisius Gemma's (1508-1555) 'De Radio Astronomica et Geometrico' (1545). This plate, showing how he observed an eclipse of the Sun on 24 January 1544, is thought to be the first illustration of a camera obscura. A camera obscura is a box or darkened room with a lens or hole through which an image of an external object is projected onto the opposite internal wall. Camera obscuras were known to the ancient Chinese and Greeks, and were used by Arab astronomers in the 10th century to observe the sun. During the Renaisance, artists used them to help them draw more accurately.