About Slave Group Control
Slave group A
ID = A ID = A ID = A
For example, if you have the slave ID set to <1> for three slave units, all three slave units will be controlled as if they were one Speedlite in slave group A.
Setting Manual Flash with the Slave Unit 
Manual flash can be set manually with the slave unit. Do this in the following cases:
(1)When you want to set the flash output with the slave units individually for wireless or manual flash, as with studio flash units.
(2)When you use Speedlite Transmitter
Hold down the <D> button for 2 sec. or more.
X <q> will blink.
Set the manual flash output. (p.19)
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