The EMF Trigger option adds the ability to set start and end camera shot trigger values.
Set the "Trigger On" value to a value above normal EMF readings.
To get an idea of the 'normal' readings, set this value to 1000, then exit to the main camera screen. Touch the [EMF Off] button to start readings. The current reading value will be displayed. Set the "Trigger On" value to at least 100 above this normal reading.
Set the "Trigger Off" value to about 50 above the normal reading, otherwise, the trigger won't turn off.
The "Trigger On" value must always be larger than the "Trigger Off" value.

The "Shot Interval" will determined the interval between each shot taken while the EMF in between the On and Off range. Set this to zero to only take one picture right when the EMF is triggered.

Here is how the Settings screen looks after purchasing the EMF Trigger Option: