camera

A pinhole camera has no lens but can nevertheless produce a sharp inverted image because only one ray from a particular point can enter the tiny pinhole aperture, and so no blurring takes place. However, the very low amount of light entering the camera also means that the film at the back must be exposed for a long time before a photographic image is produced; the camera is therefore only suitable for photographing stationary objects.

A promotional picture from about 1890 of a fashionable lady holding one of George Eastman's first Kodak box cameras, the carrying-case hanging at her side. She would have had to return the entire camera to the Rochester factory for the finished film to be processed and replaced.

The basic parts of a camera. The film is only exposed to light when the shutter is opened to take a photograph and then the aperture controls the amount of light entering the camera. The lens position is adjustable so that objects at varying distances can be brought into focus. The rays of light reflected from the object are brought together by the lens and form a sharp inverted image on the film.

Apparatus used in photography, consisting of a lens system set in a light-proof box inside of which a sensitized film or plate can be placed. The lens collects rays of light reflected from the subject and brings them together as a sharp image on the film. The opening or hole at the front of the camera, through which light enters, is called an aperture. The aperture size controls the amount of light that can enter. A shutter controls the amount of time light has to affect the film. There are small-, medium-, and large-format cameras; the format refers to the size of recorded image and the dimensions of the image obtained.

A simple camera has a fixed shutter speed and aperture, chosen so that on a sunny day the correct amount of light is admitted. More complex cameras allow the shutter speed and aperture to be adjusted; most have a built-in exposure meter to help choose the correct combination of shutter speed and aperture for the ambient conditions and subject matter. The most versatile camera is the single lens reflex (SLR) which allows the lens to be removed and special lenses attached. A pin-hole camera has a small (pin-sized) hole instead of a lens. It must be left on a firm support during exposures, which are up to ten seconds with slow film, two seconds with fast film and five minutes for paper negatives in daylight. The pin-hole camera gives sharp images from close-up to infinity.