Canon SPEEDLITE EL-1 Advanced User's Manual page 170

3.
Set sender flash firing.
Push the joystick to the left or right or turn <
firing ON / OFF, then push the joystick vertically.
• <
• <
Caution
Even when sender flash firing is set to OFF, the flash firing for controlling the
receiver unit (optical transmission) is performed. Therefore, depending on the
shooting conditions, the flash fired for controlling the receiver unit may be captured
in the picture.
>: Sender flash firing ON
>: Sender flash firing OFF
170
> to select sender flash