Leonardo da Vinci studied the camera obscura, which projects an outside scene into a dark chamber.
The device works when light passes through a small opening into an otherwise dark space. The rays form an inverted image of the outside world on the opposite surface. Leonardo investigated this phenomenon to understand vision, light, perspective, and image formation.
A camera obscura is not the same as a modern camera. It has no photographic film or electronic sensor, although its optical principle influenced later camera development. Leonardo also used the device as a way to compare the behavior of light with the workings of the human eye.
His notebooks contain detailed observations about the image, the aperture, and the geometry of light. The study demonstrates how his artistic practice and scientific investigation reinforced each other.