Near depth of field


In optics, particularly as it relates to film and photography, depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. Although a lens can precisely focus at only one distance at a time, the decrease in sharpness is gradual on each side of the focused distance, so that within the DOF, the unsharpness is imperceptible under normal viewing conditions.
For a given symmetrical lens the near depth of field, is the distance from the camera to the nearest limit of depth of field and is depended to the object distance , the lens focal length and the f-number.
(The f-number of an optical system is the ratio of the lens’s focal length to the diameter of the entrance pupil).

Related formulas


DnNear depth of field (mm)
sDistance of the subject (mm)
fFocal length (mm)
Nf-number (focal ratio) (dimensionless)
cCircle of confusion (mm)