Nikon D3 - Manual (Page 338)

312
U
a10: Vertical AF-ON Button
Choose the function assigned to the B
button for vertical shooting.
Option Description
G Same as AF-ON
Both B buttons perform the function selected
for Custom Setting a9.
A
AF-ON
(default) Pressing the vertical B button initiates
autofocus.
B AE/AF lock
Focus and exposure lock while the vertical B
button is pressed.
C AE lock only
Exposure locks while the vertical B button is
pressed.
D
AE lock (Reset
on release)
Exposure locks when the vertical B button is
pressed, and remains locked until the button is
pressed a second time, the shutter is released, or
the exposure meters turn off.
E AE lock (Hold)
Exposure locks when the vertical B button is
pressed, and remains locked until the button is
pressed a second time or the exposure meters
turn off.
F AF lock only
Focus locks while the vertical B button is
pressed.