ND Filter & Long-Exposure Calculator
Work out the new shutter speed after adding a neutral-density filter.
About this tool
A neutral-density filter and long-exposure calculator. Give it your metered base shutter speed and the ND filter you want to stack, and it tells you the corrected exposure time, formatted in seconds or minutes:seconds for long exposures. Ideal for smoothing water, blurring clouds and shooting daylight long exposures.
Frequently asked questions
How do I calculate exposure time with an ND filter?
Enter your base shutter speed and the filter strength in stops (or its ND name). The new time is the base time multiplied by 2 to the power of the stops of light it blocks.
How many stops is an ND1000 filter?
An ND1000 (also called a 10-stop or 3.0 density) filter blocks about 10 stops of light, multiplying your exposure time by 1024.
Can I enter the base shutter as a fraction?
Yes. You can type base_shutter=1/125, base_shutter=0.5, or base_shutter=2s. Long results are shown in mm:ss or h:mm:ss.
What ND filters does it know?
It maps the common names ND2 (1 stop), ND4 (2), ND8 (3), ND64 (6), ND1000 (10) and ND100000 (~16.6) among others, and also accepts nd_stops directly.