Leonardo da Vinci designed and analyzed a camera obscura, an optical device that projects an outside scene through a small opening into a dark chamber.
In a camera obscura, light travels in straight lines through the aperture. Rays from the scene cross at the opening, producing an image on the opposite surface. Leonardo’s notebooks describe the geometry and explain why the projected image appears inverted. He used the device as a way to investigate vision, perspective, and the behavior of light.
The camera obscura was not a camera in the modern photographic sense. It had no film, sensor, or chemical recording process; an observer had to view or trace the temporary image. Leonardo also did not invent the underlying phenomenon, which had been discussed by earlier scholars, but he made detailed studies that connected optics with artistic practice.