Depth of field & hyperfocal distance calculator

How deep is the sharp zone? Near and far limits, depth of field and hyperfocal distance — with sharpness defined in pixels, not in 35 mm print conventions.

Lens & focus
mm
mm
Object to lens.
What counts as sharp
Circle of confusion
µm
px
1–2 px for measurement, more for viewing.
mm
0.03 mm is the 35 mm photography convention.
Side view of the sharp zone around the focus plane (not to scale vertically), and how near and far limits move as you stop down.

Details

    How it's calculated

    Anything imaged on the sensor smaller than the circle of confusion c counts as sharp. Photography uses c = 0.03 mm (35 mm format); in machine vision a multiple of the pixel size makes more sense, typically 1–2 pixels. From that follow the hyperfocal distance H and the sharpness limits for a focus distance s (measured from the lens):

    H = f² / (N · c) + f

    near = s · (H − f) / (H + s − 2f)  ·  far = s · (H − f) / (H − s)  (∞ when s ≥ H)

    Stopping down (larger N) increases the depth of field — but also the diffraction spot. Beyond the f-number at which the Airy disc grows past about two pixels, the whole image gets softer. Check that limit with the Airy disc calculator.

    All results are planning estimates based on simplified models and manufacturer data, without guarantee. Please verify critical values against the manufacturer datasheets before you make a design decision.

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