Free tool for drone pilots who shoot video
Drone ND filter calculator
Target shutter = 1/(2 × frame rate); ND stops = log2(metered shutter denominator ÷ target denominator). In the example, 30 fps gives a target of 1/60 s. The drone meters 1/2000 s without a filter, so 2000 ÷ 60 = 33.3 times too much light, which is 5.06 stops. The nearest filter is ND32 (5 stops); with it the shutter lands at 1/62.5 s, 0.06 stops from the target.
Last updated 2026-11-12.
- Filter to use
- Target shutter (180° rule)
- Light to cut
- Stops to cut
- Shutter with that filter
- Left over after the filter
Check the inputs: frame rate between 1 and 1000, metered shutter above 0 (for 1/2000 s enter 2000).
Take it with you
Example scenarios
Three sets of example inputs worked through the same formulas as the calculator above. They are illustrations, not averages or statistics.
| Scenario | Inputs | Target shutter | Stops to cut | Filter | Shutter with filter |
|---|---|---|---|---|---|
| Low | 24 fps, metered 1/400 s | 1/48 s | 3.06 stops | ND8 | 1/50 s |
| Typical | 30 fps, metered 1/2,000 s | 1/60 s | 5.06 stops | ND32 | 1/62.5 s |
| High | 60 fps, metered 1/8,000 s | 1/120 s | 6.06 stops | ND64 | 1/125 s |
Method: Target shutter = 1/(2 × frame rate); light to cut = metered shutter denominator ÷ target denominator; stops = log2 of that; the filter is the nearest of ND4, ND8, ND16, ND32 and ND64 (2 to 6 stops), none under one stop (no filter is closer than ND4 there); above ND64 the page warns that a stronger filter is needed; shutter with the filter = metered denominator ÷ ND number, at the same ISO and aperture. Figures checked against the same formulas on 2026-11-12.
How the calculator works
The 180° rule sets the shutter to half the frame interval: 1/(2 × frame rate). At 24 fps that is 1/48 s (most drones offer 1/50 s), at 30 fps 1/60 s, at 60 fps 1/120 s. In daylight a drone camera with a fixed or narrow aperture meters a much faster shutter, so the filter has to remove the difference.
Divide the metered shutter denominator by the target denominator to see how many times too much light reaches the sensor. Each doubling is one stop, so stops = log2 of that number. ND filters are named by the same factor: ND4 cuts 2 stops, ND8 3, ND16 4, ND32 5 and ND64 6. The calculator picks the nearest one and shows the shutter you get with it at the same ISO and aperture.
Worked example
You film at 30 fps, so the target is 1/(2 × 30) = 1/60 s. On a sunny afternoon at your base ISO the drone meters 1/2000 s without a filter. 2000 ÷ 60 = 33.3, and log2(33.3) = 5.06 stops.
The nearest filter is ND32, which cuts 5 stops. The shutter then lands at 2000 ÷ 32 = 1/62.5 s, 0.06 stops faster than 1/60 s, close enough that you set 1/60 s and the exposure barely changes.
Choosing the inputs
Meter the scene you will actually fly: hover, frame the shot in auto exposure at your lowest ISO and read the shutter. Sky, snow, water and backlight change the reading; light also changes through the day, so re-meter when the sun moves or clouds come in.
When the result falls between two filters, the leftover stops tell you which way you are off. A small positive value means the shutter is still slightly fast; a negative value means slightly slow. Many pilots accept about a third of a stop either way, or nudge ISO if the camera allows it. For fast FPV or shaky shots some prefer a faster shutter than the 180° rule; that is a style choice, not an error.
What this tool does not do
It uses the ND numbers ND4 to ND64 only; variable ND filters and polarising ND combinations cut a range or a little extra. It does not know your drone's aperture or ISO limits, and it does not read your camera. It is arithmetic on the shutter you enter.
Questions
What if the calculator says no filter is needed?
Your metered shutter is already within half a stop of the target, which happens in dull light or at higher frame rates. Fly without a filter or use a light one if the light will rise.
Why does the 180° rule matter?
At 1/(2 × frame rate) each frame holds about as much motion blur as the eye expects, so movement looks smooth. Much faster shutters make motion look choppy, especially in pans and with moving water or traffic.
Does this page store my numbers?
No. The math runs in your browser; nothing is sent or saved.
Made by Bardach Technologies. We also make the Aerialgrade Drone LUT Pack: 20 .cube files with 4 conversion LUTs from D-Log to Rec.709 and 8 looks, each look as a D-Log-in and a Rec.709-in file, plus a PDF guide (USD 39.99, one-time purchase on Gumroad). It has no D-Log M conversion of its own: D-Log M footage is converted with DJI's free LUT first. This calculator is free and needs no sign-up; nothing is charged on this page. Get the Aerialgrade Drone LUT Pack on Gumroad (USD 39.99)