In photography, a camera or a camera cartridge (Camera obscura) is usually used as a photographing device, and an optical film or a digital memory card is used as a recording medium. But there are exceptions, such as Man Ray 's physical projection method (rayographs) is the use of shadow in the paper on imaging without the need to use the camera.

Most with a series of photographic lens consisting of a lens , the light will be refracted to focus after the film or CCD optical sensing medium, the film itself is a storage medium to store a chemical change signal. The CCD will convert the light into an electronic signal and store it with a digital memory card . The stored signals can be restored to optical signals in some ways and viewed with photos or monitors . In addition to lenses composed of lenses, a few lenses are composed of mirrors or mirrors with lenses.