Neutral Density Quick Conversion Chart

on October 07, 2022
Marumi Neutral Density Filter Line-up

Have you already heard the word of photography like “F-stops”, “Filter Factor”, “Optical Density” or “Transmission rate”, and somehow you vaguely understand what they really mean?

If yes, the chart and description below enable you precisely to understand the correlation comprehensively.

Neutral Density Filter allows you to reduce only the amount of light, but how much and how to express?

Taking ND4(0.6) as an example, the amount of light decreases down to 1/4, which is 25% transmittance rate, equivalent to 2 stops. 1 stop values Optical Density of 0.3, then 2 stops 0.6,

In photographic industry in general, the number of Filter Factor represents ND numbering (e.g. ND4).
In cinema industry on the other hand, the number of Optical Density represents ND numbering. (e.g. ND0.6)

These sounds confusing, but if you purchse marumi ND products, take a look at this chart for the help of calculation.

Thank you for your attention!


Marumi team,