Leonardo da Vinci studied the camera obscura, an optical device that projects an outside scene into a dark room through a small opening.
In a camera obscura, light travels in straight lines through a pinhole or lens and forms an inverted image on an opposite surface. Leonardo described the effect in his notebooks and used it to investigate vision, light, and perspective. His observations helped connect the geometry of image formation with the way the eye receives visual information.
Leonardo did not invent the camera obscura; descriptions of the phenomenon existed in ancient Chinese and Greek writing, and Arab scholar Ibn al-Haytham analyzed it in the eleventh century. Leonardo’s importance lies in his detailed Renaissance studies and proposed applications. The device is also not the same as a modern photographic camera. A camera obscura forms a temporary optical image, while photography records an image on a light-sensitive material. Artists later used camera obscura devices as aids for perspective, but evidence that Leonardo routinely painted with one remains debated.