ND Filter Calculator

Pick your base shutter speed and ND filter — get the new long-exposure shutter speed, the stops added and the light-reduction factor, instantly.

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Your exposure

ND filter

Use a tripod and a remote release (or 2 s timer) for a sharp long exposure.

New shutter speed
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0stops added
0ND factor
0% light passing
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Quick scenarios
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How ND filter exposure is calculated

An ND filter blocks light in "stops", and each stop doubles the exposure time needed:

New shutter = Base shutter × 2stops

An N-stop filter halves the light N times, so the sensor needs 2N times longer for the same exposure. That's why an ND1000 (10 stops) turns 1/125 s into several seconds. The tool also gives the ND factor and the percentage of light passing, so you know exactly how much it darkens.

Example: a long exposure with an ND1000 filter

You shoot at 1/125 s and fit an ND1000 (10 stops):

  • ND factor = 210 = 1024×.
  • New shutter = 1/125 × 1024 = 8.2 s exposure.
  • Only ~0.1% of the original light passes.

With an ND8 (3 stops), the same 1/125 s would only become 1/16 s — ideal for softening motion without darkening as much.

ND filter FAQ

How does an ND filter affect shutter speed?
Each stop of neutral density doubles the exposure time. A 3-stop ND multiplies the shutter speed by 8; a 10-stop (ND1000) by 1024. The calculator does the conversion instantly.
What is an ND1000?
It is a 10-stop filter that passes only 1/1024 of the light (~0.1%). It is used for long exposures in daylight: silky water, moving clouds, empty streets.
Which filter do I use for silky water?
It depends on the light: in moderate light an ND8-ND64 gets you to 1/4-1 s; in bright sun or for strong effects, an ND1000. Try the presets in the tool.
Can I stack several ND filters?
Yes: the stops add up. An ND8 (3 stops) + an ND64 (6 stops) equals 9 stops. Watch for vignetting and possible colour cast when stacking.
Do I need a tripod for strong ND filters?
Essential. With multi-second exposures, the slightest movement ruins sharpness; use a tripod and a remote release or the 2-second timer.