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Photography Calculators

Equivalent Exposure Calculator

Swap aperture, shutter or ISO and keep the same exposure — the reciprocity triangle.

Enter values

Results update as you type.

Result

New shutter speed

1/61 s

Stops of change
3.029
Exposure time in seconds
0.01633
Original shutter
1/500 s
Light change
Less light by 3.03 stops
Times longer
8.163 ×
Tripod needed?
Hand holding should be fine

About the Equivalent Exposure Calculator

Swap aperture, shutter or ISO and keep the same exposure — the reciprocity triangle.

Also known as: exposure triangle calculator, stops calculator, reciprocity calculator, nd filter exposure.

How to use this calculator

  1. Enter original aperture, original shutter (1/x s), original iso, change the and the other fields.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

Every stop doubles or halves the light: t₂ = t₁ × 2^stops

Worked example

Using the values pre-filled in the calculator above:

  • Original aperture = 2.8
  • Original shutter (1/x s) = 500
  • Original ISO = 400
  • Change the: Aperture
  • New aperture = 8

the calculator returns:

  • New shutter speed: 1/61 s
  • Stops of change: 3.029
  • Exposure time in seconds: 0.01633
  • Original shutter: 1/500 s