Depth of Field
In optics, particularly film and photography, the depth of field (DOF) is the distance in front of and behind the subject which appears to be in focus. For any given lens setting, there is only one distance at which a subject is precisely in focus, but focus falls off gradually on either side of that distance, so there is a region in which the blurring is tolerable. This region is greater behind the point of focus than it is in front, as the angle of the light rays change more rapidly; they approach being parallel with increasing distance.
Several factors determine whether the objective error in focus becomes noticeable. Subject matter, movement, the distance of the subject from the camera, and the way in which the image is displayed all have an influence. However, the most important factor is the actual degree of error in relation to the area of film exposed. Light from a point source at the correct distance will produce the image of a point on the film. A point farther away or nearer will produce an image in the form of a disk known as a "circle of confusion." The diameter of these circles increases with distance from the point of focus and so can be used as the measure of error or blurring of the image. Hello and welcome to PlainBlue. As mentioned earlier this is a fairly simple template, powered entirely by css and xhtml. I am also trying to make as much use of whitespace as possible. Whitespace helps keep the page looking clean and easy on the eye, whilst improving readability also. As with all my templates, a limited number of images have been used, and when they have, they've been to aid the design. This results in an easily customisable template that can be used to an array of different sites.