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Lighting Intensity For Vision Calculator

Work out lighting intensity for vision instantly with clear inputs, formula shown and shareable results.

About Lighting Intensity For Vision Calculator

Exposure at the sensor is proportional to illumination times exposure time divided by the square of the f-number. Halving exposure time or closing one full stop each double the light needed, which is why fast-moving inspection with good depth of field demands very bright strobed lighting.

Formula

Illumination scaling

required lux proportional to (reference exposure / exposure) x (f-number / reference)^2

Worked example

With the default values below, Lighting Intensity For Vision Calculator returns Illumination required of 2,005. Change any input above and every figure here is recalculated in your browser.

Inputs used

Exposure time
2 ms
Aperture f-number
4 f/
Reference illumination at f/4 and 10 ms
800 lux
Sensor gain
6 dB

Results

Illumination required
2,005 lux
Exposure factor versus reference
5.000 x
Aperture factor versus reference
1.000 x
Illumination saved by gain
49.9% %

Step by step

  1. 1Values used
  2. 2Illumination scaling
  3. 3Illumination required= 2,005 lux
  4. 4Exposure factor versus reference= 5.000 x
  5. 5Aperture factor versus reference= 1.000 x
  6. 6Illumination saved by gain= 49.9 %

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why not just raise sensor gain?

Gain amplifies noise as well as signal, degrading measurement repeatability. Light is almost always cheaper than losing precision.

Why strobe rather than use continuous light?

Strobing puts all the energy into the short exposure window, freezing motion and letting the LEDs run far above their continuous rating.

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