Somewhere I belong. I am yet to find where. Something my heart sings, I wonder what the melody is. Somewhere she dreams of me, I wonder who she is. Something my heart screams within, I wonder what it is. I am on a road, I wonder where it leads...but I know I am not the only one, look withing yourself, I know I am not alone.

Photography_DOF

The concept of DOF

Depth of field can be treated in a theoretical framework that I will refer to as a concept. This concept is very useful because it enables extensive calculations and comparisons within the relatively simple theory of Gaussian optics. For this purpose it is assumed that the lenses are free of aberrations and that diffraction is nonexistent. The film (or digital sensor) is supposed a grainless recorder of the finest details, so that the image can be freely enlarged without loss of definition. All this is not true, but as long as we restrict ourselves to 'normal' photographic scenarios, the concept can be equated to practice with some confidence. The theory is on a separate page to preserve readability, but I will occasionally refer to an equation.

For more, click on the link below.

Source: http://toothwalker.org/optics/dof.html