PHOTOGRAPHY

The word “photography” is derived from two Greek words which together mean “to draw by light”. 

To produce a photography with a camera, the image of an object is obtained by the action of light on a prepared surface sensitive to light.Taking a photography with a modern camera is a comparatively simple process compared with that which produced some of the early photography. Cameras were large and cumbersome to handle, and, when assembled in position, had to be carefully focused on the ground glass.
     

The exposure was made by removing a lens cover, and counting the length of the exposure in seconds. 

There was also the tedious task of preparing a sensitive glass plate, for which the photographer had to carry with him a portable dark-room and chemical solutions, or a large plate-changing box. Today, cameras are loaded in daylight with one of three forms of flexible roll film, each of which offers the choice of black-and-white negative film, colour negative film, or colour reversal film.
      

In essence, a camera is a light-tight box, with matt-black interior surfaces, carrying in its front panel a lens placed so as to form a sharp image of distant objects on a light-sensitive film held in a vertical plane at the back of the box. In addition, there is a shutter which can be made to open momentarily to pass the image-forming beam of light: and the lens usually permits a limited movement forward to bring closer objects into focus.Lenses fitted to popular cameras have shown considerable advance in construction and scope.
     

Today, except in the cheapest cameras, a lens will be an assembly of three or more glasses, all ground and polished to exact curved surfaces and opening to a wide aperture. 

The aperture of a lens is a measure of its light-transmitting power.  It is rarely desirable to make full use of this power, and lenses are provided with an iris diaphragm, consisting of a system of thin metal leaves which can be made to close down, to diminish the central circular hole through which the light passes. As the aperture is made smaller, the exposure effect is reduced. Some cameras have automatic exposure control in which the light-measuring mechanism adjusts the lens aperture.
      

The camera may incorporate either a lens shutter, in which a set of thin, metal leaves within the lens separate to form an opening; or a focal-plane shutter, having a pair of opaque, flexible curtains arranged to run across just in front of the film, one a little in advance of the other. Even the simplest shutters allow the choice of two or three speeds which are short enough for the making of a snap shot exposure with the camera hand-held.
      

More expensive cameras provide a wider range of speeds-typically from one second down to 1/500th second (lens shutter) or 1/1000th (focal plane).Camera development has been a story of decreasing image dimensions, increasing mechanical complication, and growing simplicity in operation. During the first half of this century, box form or folding cameras taking roll film of moderately large size were mainly used.
      

They were increasingly replaced by smaller models giving pictures of reduced size. Only two types remained in wide use by the end of the fifties; the so-called miniature cameras, which accept cassettes of film 35mm wide giving twenty or thirty-six pictures of size 24 x 36mm; and roll-film reflex cameras which give twelve pictures of size 6 x 6cm on roll-film spools. A recently introduced type of camera takes quick-load drop-in cartridges (No. 126) giving twelve 28 x 28mm pictures. This makes for easy camera loading and is almost invariably used by young photographers today.
       

The instant-loading type of camera employs a special film cartridge which allows 35mm film with opaque paper strips at each end to pass from a ‘feed’ chamber to a ‘take’ chamber along a connecting channel which has a cut-out rectangular opening where the image is recorded.

A feature common to all three types of camera is that the pictures they yield are too small without enlargement, and some form of projection is involved. The most notable, recent development in camera design is the use of photo-electric devices within the camera, which either   provide a guide to the user in his setting of the exposure adjustments,  or else take over control of the exposure settings.
      

There has also been noteworthy advance in making exposures by flash. Not only can bulbs, flash cubes, or small electronic flash units be more conveniently used on today’s popular cameras, but also extremely sophisticated flash units have been developed which automatically cut the length of the flash units have been exposure. They have a measuring element incorporated in the flash unit which measures the light reflected back from the object I think cameras are tricky things that give us shadows instead of concrete and tangible forms. 

Cameras, through the pictures they produce, are good recorders because photographs remind us of objects we have seen, places we have visited, people and friends we have met.
     

Sometimes, these pictures represent our experiences with amazing freshness. Everybody should own a camera and learnt photography.