A digital image forms thanks to the capacity of the silicon sensor to produce an electric current when it receives light. It is not yet an image, in the same way that the data sent by the retina of our eye to our brain cannot yet be seen. Each dot of this “potential” photograph has to be coded in numbers, according to the binary system acceptable to the computer, in order to become a pixel, or the digital representation of a dot in the picture. Together, the many pixels still have to undergo a number of mathematical operations before becoming a digital photograph.
At the beginning of digital imagery, these calculations enabled the equalizing of film performance, but the digital revolution has only just begun. In the near future, digital image processing and the new optics and new sensors will certainly generate advances which are unimaginable today.
Located at the heart of the camera, the sensor has replaced film. It is made up of many micro structures deposited on a material with a particular electric behaviour, called a semi-conductor, in this case, silicon. The object manufactured is called a “wafer”, like the thin biscuit in baking.