Calculate neutral density

Convert an ND filter’s stop rating into an exposure-equivalent shutter time.

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ToolNeutral Density Calculator
Input
Output
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Preview

How it works

An n-stop filter multiplies base shutter time by 2ⁿ, then the result is displayed as seconds or a reciprocal shutter speed. Aperture and ISO remain unchanged.

  • Each stop doubles exposure time.
  • The result is a recommendation rather than a motion-rendering guarantee.

Worked example

ND1000 (10 stops) on a fast base exposure
Base shutter speed of 1/125s with a 10-stop filter added
Input
											Base shutter speed s: 0.008
Nd stops: 10
Output
												New shutter speed s: 8.192
New shutter speed formatted: 8.2s
Stops added: 10
Multiplier: 1024

When to use this

Landscape photographers preserve wide apertures, waterfall shots lengthen time, and cinematographers compare filters before setting shutter angle.

Edge cases

  • Ten stops multiply time by 1,024, so 1/125 s becomes about 8.2 s.
  • Real transmission can differ from the label and add colour cast.
  • Long exposures add noise and motion blur despite exposure equivalence.