A pinhole camera, also known as camera obscura, or "dark chamber", is a simple optical imaging device in the shape of a closed box or chamber. In one of its sides is a small hole which, via the rectilinear propagation of light, creates an image of the outside space on the opposite side of the box.
History*
Images created via a small opening will be found in the natural environment and in everyday life, and people in various parts of the world have been observing them since ancient times. Probably the earliest surviving description of this kind of observation dates from the 5th century BC, written by Chinese philosopher Mo Ti. In the Western hemisphere, Aristotle in 4 BC was asking, without receiving any satisfactory answer, why sunlight passing through quadrilaterals, for example, one of the holes in wickerwork, does not create an angled image, but a round one instead, and why the image of the solar eclipse passing through a sieve, the leaves of a tree or the gaps between crossed fingers creates a crescent on the ground. In 10 AD the Arabian physicist and mathematician Ibn al-Haitham, known as Alhazen, studied the reverse image formed by a tiny hole and indicated the rectilinear propagation of light. There was another scholar during the Middle Ages who was familiar with the principle of the camera obscura, namely the English monk, philosopher and scientist Roger Bacon. It was not until the manuscript Codex atlanticus (c. 1485) that the first detailed description of the pinhole camera was set down by Italian artist and inventor Leonardo da Vinci, who used it to study perspective.
Initially, the camera obscura was, in fact, a room where the image was projected onto one of the walls through an opening in the opposite wall. It was used to observe the solar eclipse and to examine the laws of projection. It later became a portable instrument which was perfected with a converging lens. Instruments of this kind were often used as drawing aids and, at the dawn of photographic history, they formed the basis for the construction of the camera. The pinhole camera was finally also applied in modern science – during the mid-20th century scientists discovered that it could be used to photograph X-ray radiation and gamma rays, which the ordinary lens absorbs. As a result, the pinhole camera then found its way onto spacecraft and into space itself.
While the first photograph taken with a pinhole camera was the work of Scottish scientist Sir David Brewster back in 1850, the technique became more established in photography during the late 19th century when it was noted for the soft outlines it produced, as opposed to lenses generating perfect, sharp images. The pinhole camera was later abandoned and it wasn't until the end of the 1960s that several artists began using it in their experiments, thus awakening renewed interest in this simple photographic apparatus which endures to this day.