GlenCalc

ND filter calculator

ND filters are labeled in stops, ND factor (ND8, ND1000) or optical density (0.9, 3.0). Each stop doubles the exposure time.

Your answer

Shutter speed with filter8.2 s
Filter strength10 stops

Worked out in your browser. Nothing you type is sent to a server.

How we worked it out

Updated as you change the numbers.

  1. Stops = log₂(ND factor) = density ÷ 0.301. New time = old time × 2^stops.

Method and assumptions

A 10-stop filter (ND1000, density 3.0) multiplies the exposure time by 1,024. Very strong filters can add a color cast and the exposure may need a little extra.

Questions

What is 1/125 s with a 10-stop ND filter?

About 8 seconds.

Sources

Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.

Embed this calculator on your site

Free to use. Paste this where you want the calculator; it runs in your visitors’ browsers, sets no cookies and sends nothing to us.

Related calculators