What determines depth of field?

Four factors: aperture (wider = shallower DOF), focal length (longer = shallower DOF at same framing), subject distance (closer = shallower DOF), and sensor size (larger sensor = shallower DOF at equivalent framing). Aperture and distance have the most impact.

What is the circle of confusion?

The circle of confusion (CoC) is the largest blur spot that still appears acceptably sharp. It depends on sensor size, viewing distance and print size. Standard values are 0.029mm for full frame, 0.019mm for APS-C, and 0.015mm for Micro Four Thirds.

Is DOF equal in front and behind the focus point?

No. At normal distances, roughly 1/3 of the DOF is in front and 2/3 behind the focus point. At macro distances, it becomes closer to 1:1. At the hyperfocal distance, 50% is in front and infinity behind.

How is depth of field calculated?

DOF uses the thin lens approximation. Near limit Dn = H×u/(H+u-f) and far limit Df = H×u/(H-u+f), where H is the hyperfocal distance, u is the focus distance, and f is focal length. H = f²/(N×c) + f, where N is f-number and c is circle of confusion.

PhotoCalcs

DOF Calculator — Depth of Field

Calculate the near focus limit, far focus limit and total depth of field for any lens, aperture and distance combination.

Focal Length

Aperture (f-number)

Subject Distance

Sensor Size

Determines the circle of confusion

How We Calculate This

This calculator uses the standard thin-lens depth of field equations:

Hyperfocal Distance

H = f² / (N × c) + f

Near and Far Focus Limits

D_near = (H × u) / (H + u - f)

D_far = (H × u) / (H - u + f)

Where f = focal length, N = f-number, c = circle of confusion, u = focus distance. When u ≥ H, the far limit extends to infinity.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.