How the depth of field calculator works
What actually controls DoF
Three levers: aperture (each stop ā Ā±40% depth), subject distance (halving distance quarters the DoF ā the dominant variable), and focal length (longer lenses thin focus at the same framing). The "crop sensor deepens DoF" folklore is mostly the shorter focal lengths crop bodies use for the same framing.
Hyperfocal: the landscape cheat code
Focus at hyperfocal distance H and everything from H/2 to infinity falls within acceptable sharpness ā the maximum DoF for the aperture without stopping down into diffraction. The formula (fĀ²/(NĀ·c) + f) lives in every DoF app; the calculator shows it for your exact lens, and landscape work never guesses focus again.
Acceptable sharpness is a choice
DoF math runs on the circle of confusion ā the blur size a viewer accepts. CoC values encode viewing size and acuity assumptions; pixel-peeping at 200% narrows DoF far below the calculator's numbers. The math describes the print; the artist decides how the print is viewed.