Choose the shot and read the light. Get the filter, shutter speed, ISO, and white balance to fit before the aircraft leaves the ground.
An ND filter is darkened glass that fits over the camera lens and reduces the amount of light reaching the sensor. The word neutral is critical — it reduces all wavelengths equally, so it should not shift the colour of your footage. Well-made filters stay neutral; poor glass can introduce a magenta or green cast that is difficult to correct later.
Think of it as sunglasses for your camera. It lets you use slower shutter speeds in bright conditions without overexposing the image.
Each "stop" halves the amount of light. The ND number is the ratio of light transmitted. ND16 passes 1/16th of the light — that's 4 stops. Each stop lets you halve your shutter speed:
| ND Filter | Stops | Light transmitted | Shutter effect | When to reach for it |
|---|---|---|---|---|
| No filter | 0 | 100% | No change | Indoor · overcast dawn · survey |
| ND4 | 2 | 25% | 4× slower | Heavy overcast · dusk · winter UK |
| ND8 | 3 | 12.5% | 8× slower | Overcast · early morning · slow-mo |
| ND16 | 4 | 6.25% | 16× slower | Bright overcast · typical Devon — most used |
| ND32 | 5 | 3.1% | 32× slower | Thin cloud · hazy sun · morning |
| ND64 | 6 | 1.6% | 64× slower | Clear sunny day · bright surfaces |
| ND128 | 7 | 0.8% | 128× slower | Bright sun · slow timelapse |
| ND256 | 8 | 0.4% | 256× slower | Extreme direct sun · midday peak |
Each block represents one ND tier. The full bar = no filter. Darker sections show how much light you're blocking. ND256 blocks all but the rightmost sliver.
For cinema to look natural, each frame needs a specific amount of motion blur. Too fast a shutter and movement looks jittery and strobe-like — called the "saving private ryan" effect when pushed to extremes. The human eye evolved seeing motion blur; removing it entirely feels wrong.
The rule: shutter speed = 2 × frame rate. At 25fps, target 1/50s. At 30fps, target 1/60s. This matches how 35mm film cameras worked — the rotating shutter exposed each frame for half its cycle.
| Frame rate | Target shutter | 180° rule result | ND needed (bright overcast Devon) |
|---|---|---|---|
| 24 fps | 1/48s → use 1/50s | Most cinematic — the film standard | ND16–ND32 |
| 25 fps | 1/50s | UK broadcast standard | ND16–ND32 |
| 30 fps | 1/60s | Common drone/YouTube standard | ND16–ND64 |
| 60 fps | 1/120s | For slow-motion edit at 24fps (2.5× slow) | ND8–ND16 |
| 100 fps | 1/200s | Extreme slow-mo · Mini 4 Pro 4K/100fps | ND4–ND8 |
The goal is to reach your target shutter speed (from the 180° rule) at ISO 100. If you're overexposed at 1/50s with no filter, add ND until the exposure is correct. If you're underexposed, move to a lower ND or remove the filter.
| Setting | Value | Why |
|---|---|---|
| Resolution | 4K/25fps or 4K/30fps | Plenty of data, natural motion, easy edit |
| Shutter | 1/50s (25fps) or 1/60s (30fps) | 180° rule — natural motion blur |
| ISO | 100 | Cleanest image, lowest noise |
| White balance | Fixed — Sunny or Cloudy | Never Auto — shifts between clips |
| Colour profile | D-Log M or Normal | D-Log M for colour grade; Normal for straight-to-edit |
| Sharpness | -1 or -2 | Reduce in-camera sharpening — recover in post |
| Noise reduction | Off or -1 | Let post-processing handle it with more control |
| EIS | RockSteady or HorizonSteady | RockSteady for most shots; HorizonSteady for orbital banking |
| Setting | Value | Why |
|---|---|---|
| Mode | Photo (not video) | Full 48MP resolution per frame |
| Shutter | 1/1000s minimum | Freeze motion — no blur between survey frames |
| ISO | 100 (200 max) | Minimum noise for clean reconstruction |
| White balance | Fixed Sunny or Cloudy | Consistent colour across all frames for matching |
| Format | JPEG + RAW | JPEG for fast COLMAP; RAW for archival and best results |
| ND filter | None needed | Fast shutter doesn't need light reduction |
| EIS | Off | EIS crops the frame — reduces effective area for reconstruction |
| Sharpness | 0 or +1 | More detail for feature matching |
Auto white balance sounds convenient but it shifts the colour temperature between frames — sometimes dramatically as the drone banks into or away from the sun. In cinematic work this creates colour flicker between clips. In photogrammetry it causes colour inconsistency between frames that confuses the feature matcher.
The correct approach: set white balance to Sunny (around 5600K) for direct sun or mixed, and Cloudy (around 6500K) for overcast. Set it before takeoff. Don't touch it during the shoot.
D-Log M is a flat, low-contrast colour profile that preserves more dynamic range by not clipping highlights or crushing shadows. The footage looks washed out and desaturated straight out of camera — this is intentional. You apply a LUT (look-up table) in post to restore colour and contrast, with far more flexibility than footage shot in Normal mode.
Use D-Log M when: shooting in mixed light conditions, you plan to colour grade in DaVinci or Premiere, or you're shooting alongside ground footage and need to match colour later. Use Normal when: you want footage ready to share immediately and won't be grading.