Where’s the Lens?
Pinhole photography is lens-less photography. A tiny hole replaces the lens. Light passes through the hole and an image is formed in the camera.
The basic optical principles of the pinhole are commented on in Chinese texts from the fifth century BC. Chinese writers had discovered by experiments that light travels in straight lines.
Pinhole photography became popular in the 1890s. Commercial pinhole cameras were sold in Europe, the United States and in Japan. By the 1930s the technique was hardly remembered, or only used in teaching.
Basically a pinhole camera is a light-tight box with a tiny hole in one end and film or photographic paper in the other. Exposures can be long, ranging from half a few seconds to several hours.