THE CAMERA
The camera is the device which is used to form the image, and either a film or a silicon electronic image sensor is the medium used to ‘sense’ the picture, which is either recorded on the film or in digital electronic memory provided by SD cards and other flash memory.
Photographers can operate their cameras and adjust their camera lenses so that the right amount of light is exposed to form the image on film, or on a “raw file” (in the case of digital cameras). In film cameras, the film is chemically processed into a useable image, and in modern digital cameras, there is an electronic image sensor, based on light sensitive electronics, and the resulting image is stored electronically and can be reproduced on paper.
The main controls of a modern camera will include: the lens aperture, which controls the amount of light entering the lens, which will effect the “depth of field” or the range in which objects are in sharp focus; the shutter speed which controls the amount of time that the image is exposed to the light and will effect the amount of light and “image blurring” from the subject’s motion; white balance (on digital cameras) which ensures that white light is recorded as such and that colours appear natural; metering which measures the exposure of subjects at a midtone to indicate the exposure levels of highlights and shadows; ISO speed which is used to set the film speed on film cameras and on digital cameras as an indication of the camera’s “gain from light” to numerical output, (used in conjunction with shutter speed and aperture); and Auto-focus which selects a point on the subject image upon which the camera will focus automatically.