Camera obscura ("dark room")
In the Renaissance and later centuries the pinhole was mainly used for scientific purposes in astronomy and, fitted with a lens, as a drawing aid for artists and amateur painters.
In the Renaissance and later centuries the pinhole was mainly used for scientific purposes in astronomy and, fitted with a lens, as a drawing aid for artists and amateur painters.
The Pinhole Camera works just like the human eye. The pinhole plays the role of the pupil, allowing light to enter, and the film or photographic paper plays the role of the retina, the tissue of the inner eye upon which the image is projected. A pinhole camera records larger or smaller images depending upon the length of the container used and the distance between the pinhole and the film.
Think in terms of ray tracing. Light travels in a straight line in a pinhole camera because there is no refracting or reflecting optical element to change the path of the rays of light. The bottom of the film is on the line passing through the pinhole and top of the object. Since all light must pass through the pinhole, that means the top of the object exposes the bottom of the film.