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Thin-Lens Depth of Field

Estimate near/far sharpness limits under a selected print-viewing blur tolerance.

  • Formula & worked example
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

The worked inputs demonstrate the selected model; change a known value or leave an editable unknown empty for a supported inverse.

near=sH/(H+s−f); far=sH/(H−s+f)

Worked example

Enter these known values and leave the other values blank.

Sensor size
35mm full-frame
Aperture f-stop
Model f/8
Show advanced details
Lens focal length (f)
50 mm
Focusing distance (u)
2 m
Print diagonal
30 cm
Standard viewing distance
25 cm
Actual viewing distance
25 cm
Visual acuity
5 lp/mm
Focal ratio (N)
8
Print width
24.96 cm
Print height
16.64 cm
Enlargement factor
6.934
Circle of confusion limit (C)
0.028844 mm
Depth of field (DoF)
0.744 m
DoF far limit
2.439 m
DoF near limit
1.695 m
Hyperfocal near limit
5.442 m
Hyperfocal distance (H)
10.884 m

Assumptions and limitations

  • A thin rectilinear lens and a model-specific circle of confusion determine approximate limits; perceived sharpness also depends on display and observer.
  • At or beyond the hyperfocal focus threshold, the far limit is infinity. Preset dimensions and aperture values are nominal, with custom input available.
  • Aperture choices show the actual numeric model f-number, including captured rounded fractional-stop values; choose custom for a measured lens setting.

Common questions

What does this model assume?

A thin rectilinear lens and a model-specific circle of confusion determine approximate limits; perceived sharpness also depends on display and observer. At or beyond the hyperfocal focus threshold, the far limit is infinity. Preset dimensions and aperture values are nominal, with custom input available.

How do units and inverse calculations work?

Choose compatible units for each quantity. The model converts quantities internally; supported editable fields can be solved from sufficient independent known values. Display rounding does not change the underlying value.

References

The model defines hyperfocal distance H=f+f²/(Nc). Thin-lens near/far limits must therefore use H−f in the numerator, H+s−2f or H−s in the denominator, and the far-limit threshold s=H. The captured limits mixed a different H convention and used an unrelated fixed 5 mm threshold.

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