Definition for Depth of Field
From Biology Forums Dictionary
The degree to which an image is in sharp focus in depth (usually a function of the size of the camera lens opening). In shallow focus(shallow depth of field), a very narrow zone of depth is in focus at any one time (foreground or midground or background), and everything closer and further from the camera is out of focus. In deep focus all distance planes (foreground, midground, andbackground) remain clearly in focus, from close-up range to infinity.
