ND Filters - How do the numbers correspond with f-stops?

[JohnAengus]

Greetings, new pilot here and I love it. I have the DJI 16, 64, 256 ND filters. How do these correspond with f-stops? I understand f-stops and how they would effect the exposure, but the numbers 16, 64, and 256 don't relate to anything I know.

Thanks,
John

 

[Ice_2k]

They’re powers of 2. So ND16 is 2^4, 4 stops. Using an ND16 will give a 16-times longer exposure time at the same exposure

 

[Ty Pilot]

There are also charts you can download for quick reference such as this one.

 

[JohnAengus]

So that would mean ND64 is 2^6 making it darken by 6 stops, and ND256 2^8 making it 8 stops darker?

 

[JohnAengus]

Thanks everyone! The light reduction in stops makes more sense to me.

 

[Ice_2k]

So that would mean ND64 is 2^6 making it darken by 6 stops, and ND256 2^8 making it 8 stops darker?

Yup

 

[Meta4]

Thanks everyone! The light reduction in stops makes more sense to me.

Here's where the numbers come from.
An ND 16 lets 1/16th of the light through.
AN ND64 lets 1/64th of the light through etc.

 

[JohnAengus]

Thank you