ND Filters 101: A Practical Guide for Drone Pilots
Learn how neutral density filters work, why they matter for cinematic footage, and how to choose the right ND filter for your drone. Includes a practical ND strength chart.
Key Takeaways
- ✓ND filters reduce light entering the camera, allowing you to use slower shutter speeds for natural motion blur
- ✓The 180° shutter rule (shutter = 2× frame rate) creates smooth, cinematic footage
- ✓ND strength is measured in stops or ND numbers (ND8 = 3 stops, ND16 = 4 stops, etc.)
- ✓Choose ND strength based on lighting conditions: ND8–ND16 for overcast, ND32–ND64 for sunny days
- ✓Always use ND filters for video; for photos, they're optional unless you want long exposures
If you've ever noticed that your drone footage looks "too sharp" or jittery—like a soap opera instead of a movie—the problem is likely your shutter speed. And the solution is an ND filter.
This guide explains what ND filters are, why they matter, and how to choose the right one for your flying conditions.
What is an ND Filter?
An ND (Neutral Density) filter is a darkened glass or resin filter that mounts in front of your drone's camera lens. It reduces the amount of light hitting the sensor—without changing colors or contrast.
Think of it as "sunglasses for your camera."
Why Can't I Just Lower ISO or Close the Aperture?
Drones have fixed apertures (usually f/2.8 or f/1.7). You can't close them down like you would on a DSLR.
ISO should stay at base (100–200) for cleanest image quality. Raising ISO adds noise; lowering it (if even possible) doesn't help in bright light.
That leaves shutter speed as the only exposure variable—but if you make it too fast (e.g., 1/1000s), you lose motion blur, which is essential for smooth, natural-looking video.
Motion blur is the slight streaking of moving objects between frames. It's what makes 24fps cinema look smooth. Without it, footage looks stuttery and overly crisp—the "video" look instead of the "film" look.
The 180° Shutter Rule
The golden rule for cinematic video is:
Shutter speed = 2× frame rate
| Frame Rate | Ideal Shutter Speed |
|---|---|
| 24 fps | 1/50s |
| 30 fps | 1/60s |
| 60 fps | 1/120s |
| 120 fps (slow-mo) | 1/240s |
This is called the 180° shutter angle rule (from film cameras) and produces the right amount of motion blur for natural-looking movement.
The Problem: Bright Daylight
On a sunny day, shooting at 1/50s (for 24fps) would massively overexpose your footage. Your camera wants to use 1/500s or faster—but that kills motion blur.
Enter the ND filter: It blocks 3–5 stops of light, allowing you to keep 1/50s shutter while maintaining correct exposure.
Some pilots disable the 180° rule for action shots (fast pans, racing drones). But for smooth, cinematic landscapes or real estate, stick to the rule.
ND Filter Strengths Explained
ND filters are rated by:
- ND number (e.g., ND8, ND16, ND32)
- Stops (light reduction in f-stops)
| ND4 | 2 stops | Hazy/overcast |
| ND8 | 3 stops | Partly cloudy |
| ND16 | 4 stops | Bright sun, early morning/late afternoon |
| ND32 | 5 stops | Midday sun |
| ND64 | 6 stops | Very bright (snow, water reflections) |
| ND128 | 7 stops | Extreme brightness (rare for drones) |
How to Read the ND Number
The ND number is how much light is transmitted:
- ND8 transmits 1/8 of light → blocks 7/8 (3 stops)
- ND16 transmits 1/16 → blocks 15/16 (4 stops)
- ND32 transmits 1/32 → blocks 31/32 (5 stops)
Rule of thumb:
- Overcast/cloudy: ND8 or ND16
- Sunny: ND16 or ND32
- Midday summer sun: ND32 or ND64
If your histogram is still clipping highlights (blown-out sky) even with ND64, you may need to:
- Shoot during golden hour instead
- Use D-Log or similar flat profile to preserve dynamic range
- Accept some highlight clipping in exchange for proper shadows
Choosing the Right ND Filter
1. Check Your Drone's Filter System
Most consumer drones use screw-on or magnetic snap-on filters. Check your drone model:
- DJI Mini/Air series: Snap-on (model-specific)
- DJI Mavic 3: Snap-on (different from Mavic 2)
- Autel EVO: Screw-on (check thread size)
Never force a filter. If it doesn't fit easily, it's the wrong model.
2. Variable vs. Fixed ND
Fixed ND (ND8, ND16, etc.):
- One filter = one strength
- Best optical quality
- Requires swapping filters when light changes
Variable ND (e.g., ND2–ND32):
- Rotate to adjust strength
- Convenient for changing conditions
- Slight risk of "X pattern" artifacts at extreme settings
Pros
- +Fixed ND: Best image quality, no artifacts
- +Fixed ND: Cheaper per filter
- +Variable ND: No need to land and swap filters
Cons
- −Fixed ND: Need to carry multiple filters
- −Fixed ND: Must land to change strength
- −Variable ND: Possible vignetting or cross-pattern at extremes
Recommendation: Start with a 3-pack of fixed ND filters (ND8, ND16, ND32). If you frequently fly in rapidly changing light (clouds moving in/out), consider a variable ND.
3. Optical Quality
High-quality ND filters:
- Use multi-coated glass or resin
- Maintain color neutrality (no green/magenta cast)
- Don't introduce softness or flare
Budget filters may add color shifts or reduce sharpness. Look for reputable brands (PolarPro, Freewell, DJI OEM, Tiffen) and avoid no-name filters on marketplaces.
Test your ND filter before a paid shoot. Fly in various light, check for color casts, and compare with no-filter shots. If you see a color shift, you can correct it in post—but it's better to start neutral.
How to Use ND Filters
Step-by-Step Workflow
- Check the weather and time of day. Bright sun = stronger ND. Overcast = lighter ND.
- Attach the filter before powering on (to avoid gimbal calibration errors).
- Power on and let gimbal calibrate.
- Set your frame rate (e.g., 24fps).
- Set shutter to 2× frame rate (e.g., 1/50s for 24fps). Many drones have a "manual" or "Shutter Priority" mode.
- Adjust ISO (keep at 100–200 if possible) or use exposure compensation to fine-tune.
- Check histogram: Should be centered, not clipping highlights or shadows.
- Fly and shoot!
If the image is too bright, you need a stronger ND (e.g., swap ND16 for ND32). If it's too dark, use a weaker ND or remove it.
Some drones (e.g., DJI Air 3) have auto-exposure with ND that adjusts ISO/aperture for you. This is fine for run-and-gun, but serious cinematographers prefer full manual control.
When NOT to Use ND Filters
- Photos (usually): ND is unnecessary for stills unless you want long exposures (e.g., silky water, motion blur in daytime)
- Low light: Remove ND at dusk/dawn or you'll underexpose
- Fast action (sports, racing): You might want faster shutter (1/500s+) to freeze motion—ND would fight you
ND Filter Packs: What to Buy
If you're buying your first set, here's what we recommend:
Beginner Pack (Fixed ND)
- ND8 (partly cloudy, golden hour)
- ND16 (general-purpose sunny day)
- ND32 (midday sun)
Cost: $30–$60 for a 3-pack from reputable brands.
Advanced Pack (Fixed ND + Polarizer)
- ND8, ND16, ND32, ND64
- ND16/PL or ND32/PL (combines ND with polarizer to cut glare from water/glass)
Cost: $60–$100 for a 4–5 pack.
Variable ND (Alternative)
- One filter (e.g., ND4–ND32 or ND8–ND128)
Cost: $40–$80.
If you primarily fly over water or snow (high reflectivity), invest in an ND/PL combo filter. The polarizer cuts glare and boosts contrast, while the ND controls exposure.
Common Mistakes and How to Avoid Them
Mistake #1: Using the Same ND All Day
Light changes constantly. A ND16 that worked at 9am will underexpose by noon. Always check your histogram and swap filters as needed.
Mistake #2: Forgetting to Remove ND at Sunset
You land, swap batteries, take off again—and your golden hour footage is underexposed because you left ND32 on. Make it a habit: Check filter before every flight.
Mistake #3: Buying Cheap Filters
A $10 ND filter can ruin a $1,000 drone's image. Color casts, softness, and vignetting are common with budget filters. Spend $30–$60 on a quality set—you won't regret it.
Mistake #4: Not Calibrating Gimbal After Installing Filter
Some drones (especially older models) need gimbal recalibration after adding a filter. If you see gimbal errors or twitching, recalibrate in the app.
FAQ
Frequently Asked Questions
Next Steps
- Buy a starter 3-pack (ND8/ND16/ND32) for your drone model.
- Practice in manual mode: Set 24fps, 1/50s shutter, and see how exposure changes with different NDs.
- Test in varying light: Fly at 10am, noon, and 4pm to learn which ND works when.
- Check histograms: Aim for a centered, bell-shaped curve—no clipping.
- Shoot a test scene: Compare footage with and without ND. You'll immediately see the difference in motion blur smoothness.
Disclaimer: This guide reflects best practices as of October 2025. Always follow your drone manufacturer's guidelines for filter installation and gimbal operation.
Last updated: October 11, 2025