Canon SPEEDLITE EL-1 Advanced User's Manual page 183

5.
Set the A:B flash ratio.
Push the joystick vertically to select an item in the figure.
Push the joystick to the left or right or turn <
compensation, and push the joystick vertically.
6.
Take the picture.
The receiver will fire at the set flash ratio.
183
> to set the amount of