How to Operate a Digital Camera

In a digital camera the scene is projected on a sensor that is covered with photosensitive receptors. Here, the effect of light falling on a point isn't a chemical transformation, but the generation of a weak electrical signal proportional to the exposure level which is then amplified and converted to information. A camera's digital sensor can be made up of many million receptors, from which the images pixels are made from. We have to have in mind that the amount of information contained in an image is huge: every point must be described with brightness intensity values (luminescence) and color. Television and video, predecessors to digital photography, were originally analogical technology : the converted the group of information into a wave that can be recorded on a magnetic tape (video cameras) or transform into a radio wave (transmission). Nonetheless, with the developing technology, digital technology has appeared, were the image's information, fixed or animated, is converted into a series of numerical values (digits). The advantages of the new technology over the old are causing a fast substitution of one for the other.

Contrary to what happens on television, were the number of points is set beforehand by the industry standard, the number of points in digital photography is only limited by the technological capacity to manage them. In the beginning of digitalization, an image that contained 5 million points couldn't be dealt with except with professional equipment. The first steps in digital treatment of high quality photographs were given in graphic art and design, were images that were originally registered on film were scanned. Any of that professional equipment was less powerful and of course much slower than any computer nowadays.

The diffusion of digital images has transformed the photography world: it is no longer necessary to develop; the digital cameras viewfinder lets us see results instantly, with which the uncertainty associated with film finally disappears; the difference between slides and negatives have disappeared, because all digital images are positive; our pictures will be prints if we print them on paper, or "slides" if we want to project them; thanks to the computer we can archive and locate images much faster; we have means to copy, edit, correct and retouch our photographs with image editing programs; printing, in black and white or in color, doesn't require a dark room because with a good printer we can get excellent quality prints; photographing with film isn't completely incompatible with this new technology, because with a medium quality scanner we can digitalize all our photographic material; digital images we obtain with a camera or with the canner, which we edit and retouch on the computer can also be sent to the lab and printed on photographic paper or on reversible film (slides); also the internet lets us share the photos with our family and friends.

Also on the professional level there has been a revolution: the digital technology is already standard in design and graphic art; the photographer has a good tool to have better control of the final product and can also turn in originals, scanned (if the pictures were made on film) and edited, on a digital support: recorded on a CD or transmitted through electronic mail. Also, the internet is a new medium, specially for photography, and the demand of digital images for web pages competes with that for printed medium. The web allows us to reach all kinds of news services and archives, get to know the work of artists and reporters and even publish our own images.