What optical device did Leonardo da Vinci study as an early camera?

Leonardo da Vinci studied the camera obscura as an early camera.

A camera obscura is a dark chamber or box with a small opening. Light passing through the opening projects an inverted image of the outside scene onto an opposite surface. Leonardo described and analyzed this effect in his notebooks while investigating vision, light, and perspective.

The device did not record an image permanently. It was an optical projection system, unlike a later photographic camera that uses a light-sensitive surface. Artists could use the projected image as an aid for studying perspective and proportions.

Leonardo was not the first person to know about the camera obscura. Ancient and medieval scholars had described related effects, but his notebooks contain detailed observations and diagrams. His studies helped connect the phenomenon with the workings of the human eye.