Depth of Field (DOF)

The Depth of Field is the viewing range in the distance within the scene will recorded as a sharp image. The DOF is very important for photography as for filming.
The image clarity or sharpness is extended for a certain range in distance further away and closer from the center point of the depth of field. The extent of this area changes depending on the focal length of the lens, the focusing distance and the aperture.

typical image with depth of field area
object and image in a regular camera or photo system
depth of field as a parameter of focal length, focusing distance and aperture

(For optical analysis only one lens is used. This theoretical lens represents the properties of the entire lens system.)