Leonardo da Vinci used the camera obscura to explain how an image forms when light passes through a small opening.
A camera obscura is a darkened room or box with a tiny aperture. Light from the outside scene travels through the opening and projects an inverted image onto the opposite surface. Leonardo described and analyzed this optical effect in his notebooks during the late fifteenth and early sixteenth centuries.
The camera obscura was not invented by Leonardo. Earlier writers, including Ibn al-Haytham, had studied related optical principles. Leonardo's contribution was his detailed observation and use of the device in investigations of vision, perspective, and light.
It is a predecessor of the photographic camera, but it records no image by itself. A modern camera adds a lens and a light-sensitive surface or electronic sensor.