Depth of Field Equations

Hyperfocal distance, near distance of acceptable sharpness, and far distance of acceptable sharpness are calculated using the following equations (from Greenleaf, Allen R., Photographic Optics, The MacMillan Company, New York, 1950, pp. 25-27):

Hyperfocal distance:

hyperfocal distance equation

Near distance of acceptable sharpness:

near distance equation

Far distance of acceptable sharpness:

far distance equation

where:
H	is the hyperfocal distance, mm
f	is the lens focal length, mm
s	is the focus distance
D_n	is the near distance for acceptable sharpness
D_f	is the far distance for acceptable sharpness
N	is the f-number
c	is the circle of confusion, mm

f-number is calculated by the definition N = 2^i/2 , where i = 1, 2, 3,... for f/1.4, f/2, f/2.8,...

Calculations using these equations must use consistent units. When focal length and circle of confusion have units of millimeters, the calculated hyperfocal distance will have units of millimeters. To convert to feet, divide H by 304.8. To convert to meters, divide H by 1000.