Design & colour
ND filter exposure calculator
Translate filter stops into exposure time, factor and optical density.
A clear answer. Here’s how.
Each stop multiplies exposure duration by two. New time = base shutter time × 2^stops; filter factor = 2^stops; optical density = stops×log₁₀(2). Supports fractional stops. Assumes an ideal neutral filter and unchanged aperture, ISO and light; filter tolerances and film reciprocity failure are excluded.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Shutter time in seconds (e.g. 1/125)
- 1/125
- Neutral-density strength (stops)
- 10
Example result
- New shutter duration (seconds)
- 8.192
- New shutter duration (minutes)
- 0.136533333333
- Filter factor
- 1,024
- Optical density
- 3.01029995664