Canon Speedlite 600EX-RT Instruction Manual - Page 65

a: Wireless Multiple Flash Shooting with Flash Ratio 3 Set flash exposure compensation as required. Press function button 3 , turn and select . Press function button 3 . Turn to set the flash exposure compensation amount, and press the button. Press function button 4 to return to the shooting-ready state. Slave Group Control Firing group A 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 Gr = A 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. For example, if you set a firing group with three slave units to , the three units are treated and 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 (1/2stop increments) when converted to number of stops. The details of the flash ratio settings are as follows. 63