A tiny hole replaces the lens. Light passes through the hole and an image is formed on the back wall of the camera. The image ends up being upside down because light travels in straight lines. Light traveling from above goes straight through the hole to the bottom of the camera wall and light traveling from below goes straight through the hole to the top of the camera wall. If looking at an outdoor scene, the image on the wall has the sky at the bottom and the ground at the top.
Pinhole cameras can be small or large.
They can be made of seashells, oatmeal boxes, film canisters, soda cans or any size box. Even cars and rooms in large buildings have been used as pinhole cameras. In the Renaissance and later centuries the pinhole was mainly used for scientific purposes in astronomy. Make a Pinhole Camera. A simple device called a pinhole camera is an easy and safe way to view the Sun.