ND Filter Calculator - Available on the Download Page
26th July 2014
Expanded and updated:
This table works for all ND filters. ISO is not a factor.
Example 1
Set your preferred aperture and meter the scene. [f11]
Note the shutter speed required. [1/160th]
Read the Exposure Value [EV] for 1/160th at f11 [EV14.3].
Read up the f11 column
A 10 stop ND filter would be 14.3-10=EV4.3
Read across from 4.3 to get the shutter speed of 6 seconds
or
A 4 stop ND filter would be 14.3-4=EV10.3
Read across from 10.3 to get the shutter speed of 1/10 of a second
Switch to Manual mode on the camera and fit the ND filter
Shoot at the required settings
Example 2
Set your preferred aperture and meter the scene. [f4]
Note the shutter speed required. [1/6th]
Read the Exposure Value [EV] for 1/6th at f4 [EV6.7].
Read up the f4 column
A 10 stop ND filter would be 6.7-10=EV-3.3
Read across from -3.3 to get the shutter speed of 166 secs [2min 46sec]
or
A 4 stop ND filter would be 6.7-4=EV2.7
Read across from 2.7 to get the shutter speed of 2.5 seconds
Switch to Manual mode on the camera and fit the ND filter
Shoot at the required settings
This table works for all ND filters. ISO is not a factor.
Example 1
Set your preferred aperture and meter the scene. [f11]
Note the shutter speed required. [1/160th]
Read the Exposure Value [EV] for 1/160th at f11 [EV14.3].
Read up the f11 column
A 10 stop ND filter would be 14.3-10=EV4.3
Read across from 4.3 to get the shutter speed of 6 seconds
or
A 4 stop ND filter would be 14.3-4=EV10.3
Read across from 10.3 to get the shutter speed of 1/10 of a second
Switch to Manual mode on the camera and fit the ND filter
Shoot at the required settings
Example 2
Set your preferred aperture and meter the scene. [f4]
Note the shutter speed required. [1/6th]
Read the Exposure Value [EV] for 1/6th at f4 [EV6.7].
Read up the f4 column
A 10 stop ND filter would be 6.7-10=EV-3.3
Read across from -3.3 to get the shutter speed of 166 secs [2min 46sec]
or
A 4 stop ND filter would be 6.7-4=EV2.7
Read across from 2.7 to get the shutter speed of 2.5 seconds
Switch to Manual mode on the camera and fit the ND filter
Shoot at the required settings