Beginner ND filters

[ash59uk]

How do you work out exposure time if using more than one ND filter? for example a ND4 + ND8, do you just add them up and look for a ND12 on the exposure table? or is that too easy?

 

[HoppyUK]

How do you work out exposure time if using more than one ND filter? for example a ND4 + ND8, do you just add them up and look for a ND12 on the exposure table? or is that too easy?

No, to add them up, you have to convert to stops first. ND4 is two stops, and ND8 is three stops. 2+3=5 stops. ND12 would be roughly 3.5 stops.

 

[ash59uk]

Many thanks Hoppy

 

[StewartR]

Or you could just multiply the numbers. ND4 + ND8 = ND32.

 

[ash59uk]

Or you could just multiply the numbers. ND4 + ND8 = ND32.

Thanks Stewart that's easy to remember.