Pinhole camera

A pinhole camera is a simple camera without a lens but with a tiny aperture, a pinhole – effectively 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, which is known as the camera obscura effect. A pinhole camera is a simple camera without a lens but with a tiny aperture, a pinhole – effectively 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, which is known as the camera obscura effect. The camera obscura or pinhole image is a natural optical phenomenon. Early known descriptions are found in the Chinese Mozi writings (circa 500 BC)and the Aristotelian Problems (circa 300 BC – 600 AD). A practical demonstration of the pinhole effect from 700 AD is still in existence at the Virupaksha Temple in Hampi, India. Starting with Alhazen (965–1039), the effect was used in dark rooms, mostly 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 that was further developed into a mobile device, first in a little tent and later in a box. The photographic camera, as developed early in the 19th century, was basically 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, and 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, pneumatics, 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 finally 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 (used for safe observation of solar eclipses) or to trace the image on paper. But it is more often 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 also for educational purposes to let pupils learn about, and experiment with, the basics of photography. Pinhole cameras with CCDs (charge-coupled devices) are sometimes used for surveillance because they are difficult to detect.