How are ND filters measured?
Table of Contents
 How are ND filters measured?
 What do the numbers mean on ND filters?
 How many stops is a 3.0 ND filter?
 How do you calculate neutral density filter?
 What are ND filters and what do they do?
 How to calculate shutter speed with ND filter?
 How is the density of a ND filter defined?
 How to calculate exposure time with 10 stops ND filter?
How are ND filters measured?
Simple Math For a 10stop ND filter, if the base shutter speed (without filter) is ¼ seconds, with the use of 10stop ND filter, the exposure time becomes ¼ x 210 = ¼ x 1000 = 250 seconds. To simplify the calculation, we always assume that 210 is equal to 1000 instead of 1024 since the difference is negligibly small.
What do the numbers mean on ND filters?
Most brands of ND filters label the nd filters with either a factor number or optical density number. But for the photographer, neither of them is referred to the number of stops by which the light is reduced. ... Numbers like 0.
How many stops is a 3.0 ND filter?
What do the numbers on ND filters mean?
Stops of Light Reduction (There are filters that are measured to a fraction of a stop, but, for simplicity, we are using whole numbers here with the exception of a few filters.)  Optical Density Number (Sometimes prefaced with an "ND" before the number) 

8  ND 2.
How do you calculate neutral density filter?Understanding Neutral Density Filters
