Drone ND filters
What an ND filter does on a drone, which density to pick for the light, and why the mount is specific to each model.
The fault the filter corrects
Drone video shot in full sun without a filter looks stuttery, almost chopped, on movement. It is neither the sensor nor the stabilisation: it is the shutter speed.
For motion to look natural, the shutter must stay open for about half the duration of a frame. At 25 frames per second, that is 1/50 of a second. In daylight, the aircraft cannot hold a speed that slow without overexposing: it climbs to 1/1000, and every frame becomes a sharp snapshot, without the slight blur that ties one frame to the next.
An ND filter is a neutral grey glass. It removes light without touching colour, and so makes the slow speed you need possible.
The rule, in one line
Shutter speed = 1 / (2 × frames per second).
| Frame rate | Target speed |
|---|---|
| 24 fps | 1/48, so 1/50 in practice |
| 25 fps | 1/50 |
| 30 fps | 1/60 |
| 50 fps | 1/100 |
| 60 fps | 1/120 |
That is the speed the filter must let you reach. The whole density choice follows from it.
Which density for which light
Each step doubles the exposure time you can hold.
| Conditions | Usual density |
|---|---|
| Overcast, end of day | ND8 |
| Hazy sky, low sun | ND16 |
| Full sun | ND32 |
| Full sun over snow, sand or water | ND64 |
⚠️ Reflections count as much as the sun. The same hour over a lake or a snowfield calls for one step more than over a forest. That is the most common underestimate.
How to check on site, in ten seconds
- Set the aircraft to manual mode
- Fix the shutter speed at the value from the table above
- Fix the sensitivity at its minimum
- Fit the filter that makes the image correctly exposed
If the image is still too bright with the filter on, go one step up. If it goes dark, one step down.
⛔ The mount is not universal
An ND filter screws or clips onto a specific gimbal. A filter made for one model will not fit another, even from the same brand and a neighbouring generation.
It is the most common buying mistake, and it happens above all when changing aircraft: you keep your set of filters, and it no longer mounts.
Check three things before ordering:
- The exact model reference, not just the range
- The weight of the filter: a stabilised gimbal carries a limited mass, and a filter that is too heavy makes the motor work continuously
- The coating of the glass: cheap glass introduces a colour cast, which is precisely what a neutral filter must not do
What you do not need
- A polarising filter in all circumstances: useful over water and glass, it darkens the sky unevenly as the drone turns
- A set of six densities: three cover the year, and the extreme steps are rarely used
- A filter for photography: in stills, the shutter speed is free. The ND filter is a video accessory
By model
Useful densities and the mount change from one aircraft to another. The dedicated pages give the detail for each model.
Where to find these accessories
These links open a search at a retailer. They are not paid links and we earn nothing on your purchases: they tell us which accessories actually interest you.