In optics, particularly as it relates to film and photography, the optical phenomenon known as depth of field (DOF) is the distance about the plane of focus (POF) where objects appear acceptability sharp in an image although an optical imaging system can precisely focus on one plane at a time. The decrease in sharpness is gradual on each side of the POF so that within the DOF the unsharpness is unperceptive under normal viewing conditions.
Shallow Depth Medium Depth Deep Depth
(Small zone of focus) (Medium zone of focus) (Large zone of focus)
(Small zone of focus) (Medium zone of focus) (Large zone of focus)