Depth of field calculator

This page is useful to calculate the depth of field when using a given lens or to choose the required aperture in order to achieve a given depth of field.

The circle of confusion c is the diameter of a circle on the image plane that can be considered a single point when the image is observed (the size of the film/imager is different that the size of the print/screen. For 35 mm photography c is usually 0.025 mm, but this value depends of course on the size of the final prints.

The hyperfocal distance H is the minimum distance from the front principal plane that will appear sharp when the lens is focuses at infinity (xo = infinity).

definition of distances
H = f^2/(N c)   ; D_f = x_o H / (H-(x_o-f))   ; D_n = x_o H / (H+(x_o-f))   ; D = D_f - D_n

Calculator for finding the depth of field for a given lens and aperture.

Focal length: f =   mm
Aperture: N =  f / 
Object distance: xo =   m
Circle of confusion: c =   mm
Hyperfocal distance: H =   m
Far depth of field: Df =   m
Near depth of field: Dn =   m
Depth of field: D =   m

Calculator for finding the required aperture for a given depth of field and a given lens.

Focal length: f =   mm
Far depth of field: Df =   m
Near depth of field: Dn =   m
Circle of confusion: c =   mm
Aperture: N =  f / 
Object (focus) distance: xo =   m
Hyperfocal distance: H =   m

The maximum possible depth of field is obtained when the lens is focused one focal length f farther than the hyperfocal distance H: everything between Dn and infinity will be sharp. The value "Infinity" can be entered for Df, but since it's case sensitive it has to be typed as shown.

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