Nikon D3X - Manual (Page 367)

341
U
f7: Customize Command Dials
This option controls the operation of the main and sub-command
dials.
Option Description
Reverse
rotation
Controls the direction of the command dials. Choose [No]
(the default option) for normal command dial operation, or
[Yes] to reverse the rotation of the command dials. This
setting also applies to the command dials for vertical
shooting.
Change
main/sub
At the default setting of [Off ], the main command dial
controls shutter speed and the sub-command dial controls
aperture. If [On] is selected, the main command dial will
control aperture and the sub-command dial shutter speed.
If [On (Mode A)] is selected, the main command dial will be
used to set aperture in exposure mode g only. This setting
also applies to the command dials for vertical shooting.