Free answer for DJI drone pilots
Which ND filter do I need for drone video?
Count the stops between the shutter speed your drone meters on its own and the shutter speed you want, then pick the ND filter with that many stops. Example: say the drone meters 1/800 s at ISO 100 and you want 1/50 s for 24 fps; 800 ÷ 50 = 16, which is 4 stops, so an ND16. Each doubling of the ND number is one more stop: ND8 is 3 stops, ND16 is 4, ND32 is 5, ND64 is 6.
Last updated 2026-11-11.
The math in one line
An ND filter's number is the factor by which it cuts the light: an ND8 lets through 1/8 of it, which is 3 stops, because 2 × 2 × 2 = 8. To keep the same exposure while you make the shutter slower, with ISO and aperture unchanged, you need a filter whose factor equals the ratio of the two shutter speeds.
Ratio = denominator of the metered shutter ÷ denominator of the target shutter. Stops = how many times you double 1 to reach that ratio.
Worked table for a 1/50 s target (24 or 25 fps)
Metered 1/400 s: 400 ÷ 50 = 8, an ND8 (3 stops). Metered 1/800 s: 16, an ND16 (4 stops). Metered 1/1600 s: 32, an ND32 (5 stops). Metered 1/3200 s: 64, an ND64 (6 stops).
At 60 fps the target is 1/120 s: metered 1/960 s gives 960 ÷ 120 = 8, an ND8; metered 1/1920 s gives 16, an ND16. When the ratio falls between two filters, for example 1/1000 s to 1/120 s (about 8.3), take the nearer filter (ND8) and let a small exposure change absorb the rest.
D-Log needs two stops more ND than D-Log M
On the Mavic 3 Pro and the Mavic 4 Pro, DJI's spec pages give D-Log an ISO floor of 400 and D-Log M an ISO floor of 100. ISO 400 is four times ISO 100, which is 2 stops more sensitive. In the same light, with shutter and aperture the same and each profile at its lowest ISO, D-Log at ISO 400 therefore needs a filter 2 stops stronger than D-Log M at ISO 100: in the 1/800 s example, where D-Log M needs an ND16 (4 stops), D-Log needs an ND64 (6 stops).
Where these numbers come from
The shutter rule of thumb (a shutter at about double the frame rate) and the ND stop values are general practice; here they are taken from a guide by Ferntech, an authorised DJI retailer, not from DJI. The DJI spec pages we read give no ND recommendation and no video shutter range for log. The ratio and stop math is plain arithmetic: each stop halves or doubles the light.
Sources
- DJI: Mavic 3 Pro specs
- DJI: Mavic 4 Pro specs
- Ferntech (authorised DJI retailer, not DJI): How to use ND filters for your drone
Read on 2026-10-29. These pages change; if a line here no longer matches, the linked page wins.
Questions
How many stops is an ND32?
5 stops: 2 × 2 × 2 × 2 × 2 = 32, so it lets through 1/32 of the light.
Do I need an ND filter to shoot D-Log M?
Only if you want to keep the shutter near double the frame rate in bright light. Without one, holding that shutter in bright light overexposes the clip unless something else, such as a faster shutter, takes the extra light away.
What if the ratio falls between two filters?
Take the nearer one: 1/1000 s to 1/120 s is a ratio of about 8.3, close to an ND8 (3 stops).
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 page is free and needs no sign-up; nothing is charged on this page. Get the Aerialgrade Drone LUT Pack on Gumroad (USD 39.99)