Design & colour

Exposure value calculator

Compare photographic settings on a logarithmic stop scale.

Exposure value calculator
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Your inputs

Enter a positive decimal or fraction, from 1e-9 to 86,400 seconds.

Results update as you type. Larger files run when you press Update result.

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Your result

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A clear answer. Here’s how.

EV=log₂(f-number²/shutter seconds). The ISO-100-normalised setting value is EV−log₂(ISO/100). One EV is a factor of two in exposure-setting ratio. These are settings calculations, not a scene light measurement; lens transmission, camera calibration, flash and reciprocity effects are excluded.

See a worked example

Worked example

A fixed demonstration, separate from the values you enter above.

Aperture f-number
8
Shutter time in seconds (e.g. 1/125)
1/125
ISO setting
100

Example result

Settings exposure value EV
12.9657842847
ISO-100-normalised setting EV
12.9657842847
Shutter duration (seconds)
0.008

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