Aperture Calculator — Find Aperture for Target DOF

Rearranging the DOF equation: N ≈ DOF × f² / (2 × c × u²), where N = f-number, DOF = desired depth, f = focal length, c = circle of confusion, u = focus distance. This gives an approximate aperture, accurate when the focus distance is much greater than the focal length.

If you need f/0.7 but your lens opens to f/1.4, you cannot achieve that DOF at that focal length and distance. Options: use a longer focal length (shallower DOF per f-stop), move closer, or use a larger sensor (smaller CoC per equivalent framing).

Apertures smaller than about f/11-f/16 (depending on sensor pixel pitch) cause diffraction softening. If you need f/22 for your DOF target, consider focus stacking at f/8 instead for sharper results with the same total depth.

For macro distances (close to the focal length), the approximation becomes less accurate. Use the full DOF calculator for precise macro results. At macro distances, DOF becomes very shallow regardless of aperture.