Cameras We all know cameras and most of us also have at least one camera. These devices are usually used in order to capture images either as still photographs or as sequences of moving images. Commonly cameras work with the light of the visible spectrum or with other portions of the electromagnetic spectrum. So a camera usually consists of some kind of enclosed hollow. This hollow usually has an opening or an aperture at one end for light to enter and it has a recording or viewing surface for capturing the light at the other end. A further important component of a camera is its lens that is positioned in front of the camera’s opening. This component is used to gather the incoming light and to focus the image or the part of the image on the recording surface. In general the exposure of an image can be controlled. So the size of the aperture as well as the brightness of the scene controls the amount of light that enters the camera during a period of time. The shutter is usually used in order to control the length of time that the light hits the recording surface. In order to get a good shot one needs to focus. So due to the optical properties of photographic lenses the objects have to be within a certain range of distances from the camera in order to be reproduced clearly. Hence a process of adjusting this range that is usually known as changing the camera’s focus is required. Several different ways of focusing a camera can be found. Further information: http://www.aria.co.uk/Products/Electronics/Cameras/
