Photography facts for kids
Photography is a way of making a picture using a camera. A person who makes pictures using a camera is called a photographer. A picture made using a camera is called a photograph or photo.
Contents
Camera
A "camera" is, in its simplest form, like a box with a hole in front of it. There is a special piece of glass in front of the hole called a lens. To take a photograph of something, the lens makes a small picture of the object inside the camera. The lens does this by focusing light. A lens in a camera works like a lens in glasses (spectacles) or a magnifying glass. One type of camera called the Pinhole camera has no lens but uses a very small hole to focus light.
To make a photograph with a camera the shutter release button is pressed. Pressing the button opens the shutter. The shutter is like a door. It covers the hole in the camera box. The shutter is behind the lens. When the shutter is closed no light can enter the camera box. When the shutter is open light can enter the camera. When the button is pressed the shutter opens and then closes. This happens very fast. The amount of time the shutter stays open for is called the shutter speed. The shutter speed can change between 1/1000th of a second (0.001 s) to a few seconds. Normally the time taken for the shutter to open and close is far less than 1 second.
Some cameras have an aperture ring. It controls how much light enters the camera box.
The photograph in a camera may be made on film or, if it is a digital camera, using an electronic sensor.
Film
The picture the lens makes is recorded on photographic film. Film is placed inside the camera box. Light coming through the lens, aperture and open shutter shines on the film. Photographic film is coated with chemicals that react when light shines on it. Letting light shine on the film is called exposing the film.
There are many different types of photographic film. There are films for taking colour photographs and films for taking black and white photographs. There are different sizes of film. The most common size is 35 mm. It is called 35 mm because the width of the film is 35 millimetres. Most cameras use 35 mm film.
Another difference between films is how sensitive they are to light. Films have a code number, called an ISO number. The ISO number tells how fast a film reacts when light shines on it. Examples of ISO numbers are ISO 50, ISO 100, IS0 200, ISO 400, ISO 800, and ISO 1600. The ISO number is sometimes called the ASA number or the film speed. When the ISO number is low, for example ISO 50, the film takes a long time to record the picture. This is called a slow film. This means the shutter has to stay open for a long time. When the ISO number is high, for example ISO 800, the picture is made in a very short time. This is a fast film. This means the shutter has to open and close quickly.
Film Processing
Once the film has been exposed it is processed. Processing has to be done in total darkness or the film will be exposed too much and the picture will be lost. Processing stops the film reacting to light any more. After the film has been processed the picture can be seen on the film.
A photographic print is a photograph made on paper. A light sensitive paper is used. The picture on the film is placed in an enlarger. An enlarger is a machine that shines light through the film and makes a bigger picture on the light sensitive paper. A chemical reaction happens in the paper, which turns the areas hit with light black when the paper is 'developed'. (The more light, the darker the area.) Developing makes the picture appear on the paper – now it is a photograph. Then the paper is put into other chemicals that make it not sensitive to light any more. This is called "fixing". Last, the paper is washed so that there are no more chemicals on it and then dried. Then it is finished.
Digital photography
Digital photography uses a digital camera. Sometimes it is called digital imaging. Like other cameras a digital camera has a lens, aperture, and shutter. The picture the lens makes is recorded by a light-sensitive electronic sensor. A digital camera does not use photographic film to record a picture. Digital photographs are stored in storage devices such as SD cards. They can later be transferred to a computer. Paper prints can also be made from digital pictures. Digital cameras are also not expensive to use, as there is no film to buy.
Taking a photograph
One of the most important things when taking a photograph is focusing the lens. If the lens is not focused well, the photograph will be blurry. Autofocus cameras focus automatically when the shutter release is pressed. There are also manual focus cameras (usually older ones).
Three other things are important when taking a photograph. These control how bright or dark the photograph will be.
- The shutter speed – how long the shutter is open for. This is written in the form "1/400," or one four-hundredth of a second.
- The aperture – how big the aperture in the lens opens. This changes how much light is let in. This is written in the form "f/5.6," which describes the ratio between focal length and the size of the aperture opening.
- The film speed – how quickly the film/sensor records the picture. This is also called ISO, and is written in the form "400."
A slower shutter speed, a bigger aperture, and faster film/higher ISO sensor all make a brighter picture. A faster shutter speed, a smaller aperture, and a slower film/lower ISO sensor all make a darker picture. A good picture is not too bright and not too dark. When it is too bright it would s called "overexposed"". An automatic camera changes these things by itself when the shutter release is pressed.
Images for kids
-
Earliest known surviving heliographic engraving, 1825, printed from a metal plate made by Nicéphore Niépce. The plate was exposed under an ordinary engraving and copied it by photographic means. This was a step towards the first permanent photograph taken with a camera.
-
View of the Boulevard du Temple, a daguerreotype made by Louis Daguerre in 1838, is generally accepted as the earliest photograph to include people. It is a view of a busy street, but because the exposure lasted for several minutes the moving traffic left no trace. Only the two men near the bottom left corner, one of them apparently having his boots polished by the other, remained in one place long enough to be visible.
-
View from the Window at Le Gras, 1826 or 1827, the earliest surviving camera photograph. Original plate (left) and colorized reoriented enhancement (right).
-
A latticed window in Lacock Abbey, England, photographed by William Fox Talbot in 1835. Shown here in positive form, this may be the oldest extant photographic negative made in a camera.
-
The first color photograph made by the three-color method suggested by James Clerk Maxwell in 1855, taken in 1861 by Thomas Sutton. The subject is a colored, tartan patterned ribbon.
-
Color photography was possible long before Kodachrome, as this 1903 portrait by Sarah Angelina Acland demonstrates, but in its earliest years, the need for special equipment, long exposures, and complicated printing processes made it extremely rare.
-
This image of the rings of Saturn is an example of the application of ultraviolet photography in astronomy
-
Devices other than cameras can be used to record images. Trichome of Arabidopsis thaliana seen via scanning electron microscope. Note that image has been edited by adding colors to clarify structure or to add an aesthetic effect. Heiti Paves from Tallinn University of Technology.
-
Classic Alfred Stieglitz photograph, The Steerage shows unique aesthetic of black-and-white photos.
-
The Musée de l'Élysée, founded in 1985 in Lausanne, was the first photography museum in Europe.
See also
In Spanish: Fotografía para niños