ND Filter
Calculate exposure time with ND filters
How to use ND Filter
- 1Enter the shutter speed you would use without the filter.
- 2Enter the filter strength in stops (e.g. ND8 = 3 stops).
- 3Read the new shutter speed needed with the ND filter attached.
What Does an ND Filter Do?
exposure time × 2^(stops)A neutral density (ND) filter reduces the light entering the lens without changing colors. It lets you use slow shutter speeds in bright light for silky water or motion blur.
Each stop of ND doubles the required exposure time, so an ND1000 lets you shoot multi-second exposures in daylight.
Frequently asked questions
What does ND8, ND64, ND1000 mean?
The number is the light reduction factor; the stop count is its base-2 log. ND8 = 3 stops, ND64 = 6 stops, ND1000 ≈ 10 stops.
Can I stack ND filters?
Yes, but combined stops add up and can push exposure so long you need a remote shutter and tripod.
Why use ND for video?
It lets you keep a cinematic aperture (shallow depth) in daylight without overexposing the frame.