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Discussion of Physics

    The physics involved with digital cameras are similar to those of a regular camera. It involves the shutter on the lens opening, and the light coming through. The main difference is that rather than transferring the picture to a roll of film, the camera must translate the image into digital information. The camera does this by gathering the light through the lens and focusing it on a CCD (charge coupled device) that changes it from light to electric impulses. After it hits the CCD, the electric impulses go to a microprocessor and are sampled and transformed to digital data. The data is then stored on the camera's hard drive or memory disk which can then be transferred to a computer to view.

A CCD illustration

    To actually make the image clear and viewable, digital information in the form of electric impulses goes through what is called a digitizer. What the digitizer does is take samples of the image from across the picture and assigns them a pixel value. The pixels are then quantized, which means they are assigned digital brightness values. For a black and white photo, this involves putting it on a scale ranging from black to white. The quality of brightness in a photo is determined by the number of bits a quantizer is. A 3-bit quantizer can render merely 8 shades of a color, while one with 8-bits can produce 256 different shades.

    The major difference in a color photograph is that the shades are defined in three different components; red, green, and blue. It then has several degrees of brightness for each color which means it is able to produce many colors. The process of splitting the image into colors is called trichromacy. The different colors in the process are then broken down into saturation which allows us to see colors such as brown and orange. The image is then transferred to data storage and able to be viewed from a computer.

    The process through which the image is concieved is now clear, but how does physics relate to it? Easy, physics is involved in the process in a lot of different ways. The refraction of light through the lens to the digitizer has to do with optics. The transfer of energy throughout the process is related to physics as well. We go mainly to technological concepts once the image goes through the calculations in the computer.

    The light that goes through the lens is the main physical part of the process. The light is reflected through the small hole in the lens and exposed to the film. If the lens was too big then too much light would go through and the image would not appear. However, if the lens was smaller the image would be very sharp and clear but also very dim and difficult to see. After this process takes place then the rest of the digitizing happens and in the end we come up with a beautiful picture.


This is a photo Cheryl took with a digital camera;
the detail that can be acchieved by using one is
evident here :)