How it works#
The calculator uses the thin-lens equations with a circle of confusion (CoC) of 0.030 mm for full frame, scaled by crop factor (0.020 mm APS-C, 0.015 mm MFT). These are the same assumptions behind lens DoF scales and suit an 8×10 in print viewed at about 25 cm.
Formulas: hyperfocal H = f²/(N·c) + f; near = s(H−f)/(H+s−2f); far = s(H−f)/(H−s) (infinite when s ≥ H).
Frequently asked questions#
Why does depth of field look shallower on my screen than the calculator says?
At 100% zoom you're looking at a much bigger 'print' than the CoC assumes. For pixel-level critical sharpness, use a smaller CoC — or treat the numbers as 'acceptably sharp at normal size'.
Is depth of field split evenly in front and behind the subject?
No. At normal distances roughly a third is in front and two-thirds behind; the split approaches 50/50 at macro distances and becomes very asymmetric near the hyperfocal distance.
Last updated October 03, 2026 · How we calculate · Sources