Digital Photography

by Roy Barker

Most serious photographers and professionals use a Single Lens Reflex camera (SLR), the definition of an SLR camera is that the image is captured exactly as you see it in the viewfinder. However there are now two types of SLR the single lens reflex film (SLRF) and the single lens digital (SLRD). They are both single lens camera, but digital does not use film and the resulting image can be processed at home with the aid of a photographic editor such as Photoshop.

The chemical component in a traditional camera is film. When film is exposed to a real image, it makes a chemical record of the pattern of light, coming through the lens. Film has a collection of light sensitive frames, suspended on a strip of plastic. Colour film has three different layers of light sensitive material, which respond to red, green and blue (known as the (RBG) values. When the film is developed, it is exposed to chemicals, which dye the separate layers of film, into a colour negative. All modern film is made up of silver halide crystals.

The digital revolution is the conversion of analog information, which is represented by a gradually fluctuating wave, to digital information represented by bits. This shift in technology has revolutionized both visual and audio information, in the form of cameras, televisions, and MP3 players. Whilst SLRF cameras relied on a chemical process to transmit an image onto film, all digital cameras have their own inbuilt computers, which records images electronically.

Essentially the digital camera represents a form the computer can understand, the information is collected in bits and bytes. Each part of the image is broken down into "pixels", which is a contraction of picture element. When monitors display colors they are arranged in rows and columns, separated into thousands of little squares of colour. They are so minute that they appear to be connected, but if you zoom into this the squares are quite separate. All these squares are the smallest dot that can be displayed by a monitor, and combined together they display the completed image.

Because of the enormous difference in the way the two types of camera work, there has been in many people's mind a huge confusion as to what type of camera to buy. Added to that there are three types of SLRD cameras. SLRF cameras had conventional shapes, because it was necessary to have room for the film, and the light path, SLRD cameras do not have these constraints.

At the lower end of the market for the digital cameras are the "Point And Shoot", their SLRF equivalent is known as "idiot Proof". They have low resolutions of between 3,000.000 and 4,000,000 million pixels. The next level is the proconsumer camera typically with a resolution of 4-5 million pixels. At the top end of the market the resolution is between 6-12 million pixels. The greater the number of pixel resolution the better the quality of the resultant image.

As with any new technology there are 'pros and cons' with both types of cameras, and it will be decades before digital cameras replace SLRF, if indeed they ever do, more likely the SLRF cameras will be retained for use in a specialist market. It is also fair to say that the quality of digital cameras has improved enormously in the last ten years, and the price has also reduced dramatically.