GigaPan EPIC Pro User Manual page 76

1/4 second meter reading. With default camera settings you
will count fourteen shutter dial changes in order to reach
1/4 second. Divide 14 by 3 and you get 4 EV with 2/3 EV
remaining. The distance from the shadow meter reading is
smaller at six shutter speed setting changes on the dial
which equals -2 EV. So the distance is 4 and 2/3 EV plus 2 EV
for a total of 6 2/3 EV distance to cover the entire range.
If you are using a Nikon {D200, D300, D300S, D700S, D3, D3s,
D3x } with a nine EV span or a Canon {1D Mark III, 1D Mark IV,
1Ds Mark III} with a span of seven EV you are able to capture
these exposures using the cameras AEB function.
You can move the center exposure which is what you set
the 'Time/Exposure' setting to and lose 2/3 stops of desired
dynamic range. Another option is to use a good neutral
density filter to shift all of the exposures to shutter speeds
that are slower than about 1/10 of a second and use the
BULB setting on the camera and the imager. If you use the
bulb setting on the camera and the imager then the imager
opens and closes the shutter instead of the camera's AEB
function. Change the imager to BULB mode by changing
the 'Options'->'Expert Options'->'Shutter Length' to
'Exposure' (bulb).
Method Two EV distance from brightest area to average
exposure by multiplying exposure by two