Photography is the process, activity and art of creating still or moving pictures by recording radiation on a radiation-sensitive medium, such as a photographic film, or electronic image sensors. Photography uses foremost radiation in the UV, visible and near-IR spectrum. For common purposes the term light is used instead of radiation. Light reflected or emitted from objects form a real image on a light sensitive area (film or plate) or a FPA pixel array sensor by means of a pin hole or lens in a device known as a camera during a timed exposure. The result on film or plate is a latent image, subsequently developed into a visual image (negative or diapositive). An image on paper base is known as a print. The result on the FPA pixel array sensor is an electrical charge at each pixel which is electronically processed and stored in a computer (raster)-image file for subsequent display or processing. Photography has many uses for business, science, manufacturing (f.i. Photolithography), art, and recreational purposes.

As far as can be ascertained, it was Sir John Herschel in a lecture before the Royal Society of London, on March 14, 1839 who made the word "photography" known to the whole world. But in an article published on February 25 of the same year in a german newspaper called the Vossische Zeitung, Johann von Maedler, a Berlin astronomer, used the word photography already. The word photography is based on the Greek ??? (photos) "light" and ????? (graphé) "representation by means of lines" or "drawing", together meaning "drawing with light".

The camera or camera obscura is the image-forming device, and photographic film or a silicon electronic image sensor is the sensing medium. The respective recording medium can be the film itself, or a digital electronic or magnetic memory.

Photographers control the camera and lens to "expose" the light recording material (such as film) to the required amount of light to form a "latent image" (on film) or "raw file" (in digital cameras) which, after appropriate processing, is converted to a usable image. Digital cameras use an electronic image sensor based on light-sensitive electronics such as charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology. The resulting digital image is stored electronically, but can be reproduced on paper or film.

The movie camera is a type of photographic camera which takes a rapid sequence of photographs on strips of film. In contrast to a still camera, which captures a single snapshot at a time, the movie camera takes a series of images, each called a "frame". This is accomplished through an intermittent mechanism. The frames are later played back in a movie projector at a specific speed, called the "frame rate" (number of frames per second). While viewing, a person's eyes and brain merge the separate pictures together to create the illusion of motion.

Photography is the result of combining several technical discoveries. Long before the first photographs were made, Chinese philosopher Mo Di and Greek mathematicians Aristotle and Euclid described a pinhole camera in the 5th and 4th centuries BC. In the 6th century CE, Byzantine mathematician Anthemius of Tralles used a type of camera obscura in his experiments, Ibn al-Haytham (Alhazen) (965–1040) studied the camera obscura and pinhole camera, Albertus Magnus (1193–1280) discovered silver nitrate, and Georges Fabricius (1516–1571) discovered silver chloride. Daniele Barbaro described a diaphragm in 1568. Wilhelm Homberg described how light darkened some chemicals (photochemical effect) in 1694. The fiction book Giphantie, published in 1760, by French author Tiphaigne de la Roche, described what can be interpreted as photography.

Invented in the first decades of the 19th century, photography (by way of the camera) seemed able to capture more detail and information than traditional mediums, such as painting and sculpting. Photography as a usable process goes back to the 1820s with the development of chemical photography. The first permanent photoetching was an image produced in 1822 by the French inventor Nicéphore Niépce, but it was destroyed by a later attempt to duplicate it. Niépce was successful again in 1825. He made the first permanent photograph from nature with a camera obscura in 1826. However, because his photographs took so long to expose (8 hours), he sought to find a new process. Working in conjunction with Louis Daguerre, they experimented with silver compounds based on a Johann Heinrich Schultz discovery in 1816 that a silver and chalk mixture darkens when exposed to light. Niépce died in 1833, but Daguerre continued the work, eventually culminating with the development of the daguerreotype in 1837. Daguerre took the first ever photo of a person in 1839 when, while taking a daguerreotype of a Paris street, a pedestrian stopped for a shoe shine, long enough to be captured by the long exposure (several minutes). Eventually, France agreed to pay Daguerre a pension for his formula, in exchange for his promise to announce his discovery to the world as the gift of France, which he did in 1839.

In photography and videography, a filter is a camera accessory consisting of an optical filter that can be inserted in the optical path. The filter can be a square or oblong shape mounted in a holder accessory, or, more commonly, a glass or plastic disk with a metal or plastic ring frame, which can be screwed in front of or clipped onto the lens.

Filters modify the images recorded. Sometimes they are used to make only subtle changes to images; other times the image would simply not be possible without them. In monochrome photography coloured filters affect the relative brightness of different colours; red lipstick may be rendered as anything from almost white to almost black with different filters. Others change the colour balance of images, so that photographs under incandescent lighting show colours as they are perceived, rather than with a reddish tinge. There are filters that distort the image in a desired way, diffusing an otherwise sharp image, adding a starry effect, etc. Supplementary close-up lenses may be classified as filters. Linear and circular polarising filters reduce oblique reflections from non-metallic surfaces.

Many filters absorb part of the light available, necessitating longer exposure. As the filter is in the optical path, any imperfections—non-flat or non-parallel surfaces, reflections (minimised by optical coating), scratches, dirt—affect the image.

There is no universal standard naming system for filters. The Wratten numbers adopted in the early twentieth century by Kodak, then a dominant force in film photography, are used by several manufacturers. Colour correction filters are often identified by a code of the form CC50Y—CC for colour correction, 50 for the strength of the filter, Y for yellow.

Optical filters are used in various areas of science, including in particular astronomy; they are essentially the same as photographic filters, but in practice often need far more accurately-controlled optical properties and precisely-defined transmission curves than filters exclusively for photographic use. Photographic filters sell in larger quantities at correspondingly lower prices than many laboratory filters. The article on optical filters has material relevant to photographic filters.

In digital photography the majority of filters used with film cameras have been rendered redundant by digital filters applied either in-camera or during post processing. Exceptions include the ultraviolet (UV) Ultra typically used to protect the front surface of the lens, the neutral density (ND) filter, the polarising filter and the infra red (IR) filter. The neutral density filter permits effects requiring wide apertures or long exposures to be applied to brightly lit scenes, while the graduated neutral density filter is useful in situations where the scene's dynamic range exceeds the capability of the sensor. Not using optical filters in front of the lens has the advantage of avoiding the reduction of image quality caused by the presence of an extra optical element in the light path and may be necessary to avoid vignetting when using wide-angle lenses.