Macro Depth of Field Calculator
Macro photography produces extremely shallow depths of field because the subject is so close to the lens. At 1:1 magnification with f/8 on a full-frame camera, the total depth of field is less than 1 mm. This calculator uses the macro depth-of-field formula based on magnification rather than subject distance, making it ideal for close-up and macro work where magnification is easier to measure than exact focus distance. Enter your magnification, aperture, and sensor's circle of confusion to find the total depth of field and the effective aperture.
Macro DOF formula
Total DOF (mm) = 2 x CoC x N x (1 + M) / M^2
Effective f-number = N x (1 + M)
Example: M = 1.0 (life-size), N = f/8, CoC = 0.025 mm. Effective f-number = 8 x 2 = f/16. Total DOF = 2 x 0.025 x 8 x (1+1) / (1^2) = 2 x 0.025 x 8 x 2 / 1 = 0.80 mm. At M = 2, same aperture: DOF = 2 x 0.025 x 8 x 3 / 4 = 0.30 mm.
Macro DOF at common magnifications (f/8, full-frame CoC 0.025 mm)
- M = 0.25 (1:4): total DOF = 2 x 0.025 x 8 x 1.25 / 0.0625 = 40 mm
- M = 0.5 (1:2): total DOF = 2 x 0.025 x 8 x 1.5 / 0.25 = 2.4 mm
- M = 1.0 (1:1): total DOF = 2 x 0.025 x 8 x 2 / 1 = 0.80 mm
- M = 2.0 (2:1): total DOF = 2 x 0.025 x 8 x 3 / 4 = 0.30 mm
- M = 4.0 (4:1): total DOF = 2 x 0.025 x 8 x 5 / 16 = 0.125 mm
Macro depth of field: frequently asked questions
Why is macro depth of field so shallow?
At life-size (1:1) magnification, the standard thin-lens DOF formulas give a total depth of field of only 2 x CoC x N x (1 + M) / M^2, where M is magnification, N is f-number, and CoC is circle of confusion. At 1:1 (M=1), f/8, CoC 0.025 mm: DOF = 2 x 0.025 x 8 x 2 / 1 = 0.8 mm total.
What is magnification in macro photography?
Magnification (M) is the ratio of the image size on the sensor to the actual subject size. M = 0.5 means the image is half life-size. M = 1.0 is life-size (1:1). M = 2.0 means the image is twice the actual size. Most dedicated macro lenses achieve at least 1:1.
How does aperture affect macro DOF?
Closing the aperture (higher f-number) increases depth of field. At M = 1.0, going from f/5.6 to f/11 roughly doubles the DOF. However, diffraction limits sharpness at very small apertures; for most macro subjects, f/8 to f/16 balances DOF and diffraction.
What is the effective f-number in macro photography?
At magnification M, the effective f-number is N_eff = N x (1 + M). At M = 1 and f/8: N_eff = 8 x 2 = f/16. This means your camera meter and depth of field should be calculated using the effective f-number for accurate exposure and DOF estimation.
What CoC should I use for macro DOF calculation?
Use your sensor's circle of confusion: full-frame 0.025-0.029 mm; APS-C 0.018-0.020 mm; Micro Four Thirds 0.015 mm. The same CoC used for standard depth-of-field calculations applies to macro, but the resulting DOF is far more sensitive to magnification changes.
Official sources
- ISO 10110: Optics and photonics, Preparation of drawings for optical elements. ISO.org.
- NIST: Optical measurement references. NIST.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.