ND Filter Exposure Calculator
Fill in the values and the answer updates as you type.
How the ND Filter Exposure Calculator works
Each stop of ND doubles the exposure time, so new time = metered time × 2^stops. A 10-stop filter is also called ND1000 or ND 3.0, because 2^10 is about 1,000 and its optical density is about 3.0. Enter 125 for 1/125 s, or 0.5 for a 2 second base exposure. Real filters can add a color cast and reciprocity effects on film. Example: A metered 1/125 s exposure with a 10-stop ND filter becomes 8.2 s (8.2 seconds).
Inputs and results
The ND Filter Exposure Calculator takes 2 inputs and gives 4 results.
What you enter
- Metered shutter speed (1 ÷ this value) (1/s) — starts at 125.
- ND filter strength (stops) — starts at 10.
What you get
- New exposure time
- New exposure time (seconds)
- ND filter factor
- Optical density
Example: ND Filter Exposure Calculator with the starting values
With metered shutter speed (1 ÷ this value) 125 1/s and nd filter strength 10 stops, the calculator returns:
| New exposure time | 8.2 s |
|---|---|
| New exposure time (seconds) | 8.2 |
| ND filter factor | 1,024 |
| Optical density | 3 |
Change any value above and the results update straight away.
ND Filter Exposure Calculator FAQ
How do I use the ND Filter Exposure Calculator?
Enter metered shutter speed (1 ÷ this value) and nd filter strength in the fields, then read new exposure time, new exposure time (seconds), nd filter factor and optical density in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the ND Filter Exposure Calculator calculate?
New exposure time after adding a neutral density filter. It returns new exposure time, new exposure time (seconds), nd filter factor and optical density from the 2 values you provide.
What values does the ND Filter Exposure Calculator start with?
It opens with metered shutter speed (1 ÷ this value) 125 1/s and nd filter strength 10 stops so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the ND Filter Exposure Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the ND Filter Exposure Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.