ND Filter Calculator
Calculate the correct shutter speed when using neutral density filters. Perfect for long exposure photography with silky water, cloud streaks, and motion blur effects.
ND Filter Calculator
Calculate exposure adjustments when using neutral density filters
Common ND Filters
ND2
1 stops • ND 0.3
ND4
2 stops • ND 0.6
ND8
3 stops • ND 0.9
ND16
4 stops • ND 1.2
ND32
5 stops • ND 1.5
ND64
6 stops • ND 1.8
ND128
7 stops • ND 2.1
ND256
8 stops • ND 2.4
Long Exposure Scenarios
Formula
New Shutter = Base Shutter × 2^stopsEach stop of ND filter doubles the required exposure time
How to Use
- 1Meter without filter — Take a light reading without the ND filter attached.
- 2Enter base shutter speed — Input the shutter speed from your meter reading.
- 3Select your ND filter — Choose your filter strength (stops or ND number).
- 4Use new shutter speed — Set your camera to the calculated shutter speed.
Frequently Asked Questions
What do ND filter numbers mean?
ND filters use different numbering systems. ND8 means 3 stops (filter factor 8), ND 0.9 means 3 stops (optical density 0.9). Each stop doubles the exposure time. ND1000 (10 stops) is popular for daytime long exposures.
Which ND filter should I buy first?
A 6-stop (ND64) or 10-stop (ND1000) filter is most versatile. 6 stops allows 1-2 second exposures in daylight, while 10 stops enables 30+ second exposures for silky water and cloud streaks.
Can I stack ND filters?
Yes, stacking filters adds their stops together. An ND8 (3 stops) plus ND64 (6 stops) equals 9 stops total. However, stacking can cause vignetting and reduce image quality.
Why are my long exposures too bright/dark?
Light can change during long exposures, and some ND filters have color casts. Bracket your exposures and check your histogram. Very long exposures may need additional compensation for reciprocity failure.
What is a variable ND filter?
Variable ND filters use two polarizing elements to adjust density from about 2-8 stops. They're convenient but can cause an "X" pattern at extreme settings and may have more color cast than fixed filters.