Depth of Field
Approximate depth of field for distant subjects. DOF increases with higher f-number (smaller aperture) and increases with the square of subject distance.
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- N = 2 (F-number)
- c = 3 m (Circle of confusion diameter)
- s = 4 m (Subject distance)
- f = 5 m (Focal length)
Result: DOF = 7.68 m
Other optics formulas with the same quantities
- Mirror Equation (Reflection) shares Focal length
- Focal Length and Radius (Reflection) shares Focal length
- Thin Lens Equation (Lenses) shares Focal length
- Lensmaker's Equation (Lenses) shares Focal length
- Lens Power (Lenses) shares Focal length
- Spherical Mirror Focal Length (Reflection) shares Focal length
Where this formula is listed
- Optics formulas, under Optical Instruments, alongside Magnifying Glass Magnification, Microscope Magnification, Telescope Magnification and Numerical Aperture.
- In the optics list it comes after F-Number (f-stop) and before Dispersion (Angular).
- Optics formula sheet, one of 34 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Depth of Field formula?
Depth of Field is written DOF ≈ 2Ncs²/f². Approximate depth of field for distant subjects. DOF increases with higher f-number (smaller aperture) and increases with the square of subject distance. It belongs to Optics, under Optical Instruments.
What are the units in DOF ≈ 2Ncs²/f²?
In SI units, DOF is depth of field, measured in m; N is f-number (dimensionless); c is circle of confusion diameter, measured in m; s is subject distance, measured in m; f is focal length, measured in m.