Nikon D750 User Manual page 378

Follow the steps below to take photographs in commander
mode.
1
Adjust settings for the built-in
flash.
Choose the flash control mode and
output level for the built-in flash.
Note that output level can not be
adjusted in – – mode.
2
Adjust settings for group A.
Choose the flash control mode and
output level for the flash units in
group A.
3
Adjust settings for group B.
Choose the flash control mode and
output level for the flash units in
group B.
4
Select the channel.
5
Press J.
350