ND Filter Calculator

Find the right ND filter strength to keep your shutter angle and exposure. Balance frame rate, aperture, ISO and ambient light for cinematic motion blur.

Input

Shutter mode

Current settings

180°

Target settings

180°

Results

  • Total ND (stops) —
  • External ND (stops) —

More details

  • Scene EV —
  • Target EV —
  • External OD —
  • External factor —
  • Round ↑ to 1/3 —
  • Nearest full ↓ —
  • Nearest full ↑ —

Related Tools

How ND Filters Work

Control Exposure Without Killing Motion

Neutral Density (ND) filters are basically sunglasses for your lens. They reduce the amount of light hitting the sensor without changing color (in an ideal world), so you can keep cinematic shutter and aperture choices even in bright daylight.

Stops = the language of ND

Every 1 stop cuts light by half. So ND 3 stops means 1/8 of the light, ND 6 stops means 1/64, and so on.

What this calculator does

You enter your current settings and your target settings. The tool computes how many stops of light you need to remove to make the exposure match, while respecting shutter angle/time and frame rate.

Pro tips

• 180° rule: For natural motion blur, shutter angle around 180° is the classic baseline (e.g., 24fps → ~1/48s).

• Internal ND: If your camera has built-in ND, set it here so the tool only tells you what you still need externally.

• Real-world ND: Filters come in steps (1/3, 1-stop, variable ND ranges). Use the rounding suggestions in More details when you want something you can actually buy/use on set.