Pinhole photography is lensless photography.
A pinhole camera is a light-tight box or container with a tiny hole at one end and film or photographic paper at the other. Through the hole, rays of reflected light thrown from the exterior world enter the box and form an image. As light travels in straight lines, the projected image appears upside-down inside the camera. Pinhole cameras are used for fun, for art, or for science. Pinhole cameras are small or large, improvised or designed with great care.