Enter the base shutter speed and the stop value of the ND filter into the calculator to determine the final shutter speed.

ND Filter Formula

The following formula is used to calculate the final shutter speed of an ND filter. 

FS = BS * 2^n
  • Where FS is the final shutter speed
  • BS is the base shutter speed
  • n is the stop value of the ND filter

To calculate the final shutter speed of an ND filter, multiply the base shutter speed by the result to the power of the ND filter.

ND Filter Definition

ND filter stands for neutral density filter and this is a filter that reduces the intensity of all wavelengths of light equally that are entering a camera.

Example Problem

How to calculate the shutter speed with an ND filter?

First, determine the base shutter speed. For this example, we will use simple round numbers to make it easier, although, in reality, these may be different. The base shutter speed is found to be 400.

Next, determine the stop value of the ND filter. In this problem, the filter is a basic 10-stop ND filter.

Finally, using the formula above, calculated the final shutter speed:

FS = BS *2^n

= 400*2^10

= 409600

FAQ

What are ND filters and why are they used?

ND filters are used to allow photographers to shoot good pictures on wide lenses in bright light without overexposing the camera.

What is an ND filter made of?

As with most filters, an ND filter is made out of glass or should be if it’s of decent quality.