ND Exposure Time
A neutral-density filter extends the required exposure time by a power-of-two factor.
ND Exposure Time
Exposure · 2 inputs
How to use this calculator
- Enter unfiltered time in s.
- Enter filter strength in stops.
- Select Calculate and keep the output unit with the answer.
Before you use the answer
Keep capture settings, physical dimensions and delivery requirements in separate columns of the job notes. A mathematically equivalent setting may change motion blur, depth of field or noise. Check an actual frame before committing an entire session to a numerical estimate.
Actual transmission, light changes and long-exposure effects can require refinement.
Does it save my inputs?
No calculation history is stored by this website. The calculator works locally in your browser. See the privacy policy for hosting and contact details.
Why might a result be approximate?
Measurement uncertainty, ideal-model assumptions and floating-point rounding can all matter. Displaying more digits does not improve the original measurement.
Related calculations
ND Stops from Factor
A filter factor describes how much longer exposure must be; its logarithm gives stops.
Open calculator ↗ND Optical Density to Stops
Optical density is based on powers of ten, while exposure stops are based on powers of two.
Open calculator ↗ND Transmission
Transmission is the fraction of incident light remaining after an ideal filter.
Open calculator ↗