A pinhole camera is a simple camera without a lens but with a tiny aperture, a pinhole – a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box, known as the camera obscura effect; the camera obscura or pinhole image is a natural optical phenomenon. Early known descriptions are found in the Aristotelian Problems. A practical demonstration of the pinhole effect from 700 AD is still in existence at the Virupaksha Temple in Hampi, India. Starting with Alhazen, the effect was used in dark rooms to study the nature of light and to safely watch solar eclipses. Giambattista della Porta wrote in 1558 in his Magia Naturalis about using a convex mirror to project the image onto paper and to use this as a drawing aid. However, about the same time the use of a lens instead of a pinhole was introduced. In the 17th century the camera obscura with a lens became a popular drawing aid, further developed into a mobile device, first in a little tent and in a box.
The photographic camera, as developed early in the 19th century, was an adaptation of the box-type camera obscura. The first known description of pinhole photography is found in the 1856 book The Stereoscope by Scottish inventor David Brewster, including the description of the idea as "a camera without lenses, with only a pin-hole". One older use of the term "pin-hole" in the context of optics was found in James Ferguson's 1764 book Lectures on select subjects in mechanics, hydrostatics and optics. Sir William Crookes and William de Wiveleslie Abney were other early photographers to try the pinhole technique. According to inventor William Kennedy Dickson, the first experiments directed at moving pictures by Thomas Edison and his researchers took place around 1887 and involved "microscopic pin-point photographs, placed on a cylindrical shell"; the size of the cylinder corresponded with their phonograph cylinder as they wanted to combine the moving images with sound recordings. Problems arose in recording clear pictures "with phenomenal speed" and the "coarseness" of the photographic emulsion when the pictures were enlarged.
The microscopic pin-point photographs were soon abandoned. In 1893 the Kinetoscope was introduced with moving pictures on celluloid film strips; the camera that recorded the images, dubbed Kinetograph, was fitted with a lens. Eugène Estanave experimented with integral photography, exhibiting a result in 1925 and publishing his findings in La Nature. After 1930 he chose to continue his experiments with pinholes replacing the lenticular screen; the image of a pinhole camera may be projected onto a translucent screen for a real-time viewing or to trace the image on paper. But it is more used without a translucent screen for pinhole photography with photographic film or photographic paper placed on the surface opposite to the pinhole aperture. A common use of pinhole photography is to capture the movement of the sun over a long period of time; this type of photography is called solargraphy. Pinhole photography is used for artistic reasons, but for educational purposes to let pupils learn about, experiment with, the basics of photography.
Pinhole cameras with CCDs are sometimes used for surveillance. Related cameras, image forming devices, or developments from it include Franke's widefield pinhole camera, the pinspeck camera, the pinhead mirror. Modern manufacturing has enabled the production of high quality pinhole lenses that can be applied to digital cameras. Pinhole photographs have nearly infinite depth of field, everything appears in focus; as there's no lens distortion, wide angle images remain rectilinear. Exposure times are long, resulting in motion blur around moving objects and the absence of objects that moved too fast. Other special features can be built into pinhole cameras such as the ability to take double images by using multiple pinholes, or the ability to take pictures in cylindrical or spherical perspective by curving the film plane. Pinhole cameras can be handmade by the photographer for a particular purpose. In its simplest form, the photographic pinhole camera can consist of a light-tight box with a pinhole in one end, a piece of film or photographic paper wedged or taped into the other end.
A flap of cardboard with a tape hinge can be used as a shutter. The pinhole may be punched or drilled using a sewing needle or small diameter bit through a piece of tinfoil or thin aluminum or brass sheet; this piece is taped to the inside of the light-tight box behind a hole cut through the box. A cylindrical oatmeal container may be made into a pinhole camera; the interior of an effective pinhole camera is black to avoid any reflection of the entering light onto the photographic material or viewing screen. Pinhole cameras can be constructed with a sliding film holder or back so the distance between the film and the pinhole can be adjusted; this allows the angle of view of the camera to be changed and the effective f-stop ratio of the camera. Moving the film closer to the pinhole will result in a wide angle field of view and a shorter exposure time. Moving the film farther away from the pinhole will result in a telephoto or narrow angle view and a longer exposure time. Pinhole cameras can be constructed by replacing the lens assembly in a conventional camera with a pinhole.
In particular, compact 35 mm cameras whose lens and focusing assembly have been damaged can be reused as pinhole cameras—maintaining the use of the shutt