Canon Speedlite ST-E3-RT Mode D'emploi page 35

Slave Group Control
Firing group A
Gr = A Gr = A
For example, if you set a firing group with three slave units to <4>,
the three units are controlled as a single firing group A with a large flash
output.
To fire the three firing groups A, B and C at the same time, set
<^>. With the <%> setting, firing group C does
not fire.
If you shoot with firing group C pointing directly toward the main subject,
overexposure may result.
The flash ratio of 8:1 to 1:1 to 1:8 is equivalent to 3:1 to 1:1 to 1:3 (1/2-
stop increments) when converted to number of stops.
The details of the flash ratio settings are as follows.
a: Wireless Multiple Flash Shooting with Flash Ratio
3
Set flash exposure compensation
as required.
If you need more flash output or wish to
perform more sophisticated lighting, you
can increase the number of slave units.
Simply set an additional slave unit to the
Gr = A
firing group (A, B or C) whose flash
output you want to increase. You can
increase the number of slave units up to
15 units in total.
Press function button 3 <F>,
turn <9> and select <6>.
Press function button 3 <B>.
Turn <9> to set the flash exposure
compensation amount, and press the
<8> button.
Press function button 4 <?> to
return to the shooting-ready state.
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