Canon SPEEDLITE EL-1 Advanced User's Manual page 143

6.
Select a firing group.
If you selected <
vertically and then push the joystick up and down, or turn <
select the group to set the flash output.
7.
Set the flash output.
Push the joystick vertically.
Push the joystick to the left or right or turn <
then push the joystick vertically.
Repeat Step 3 and 4 to set the flash output of all the groups.
8.
Take the picture.
Each group fires at the set flash output.
Caution
When high-speed sync or optical transmission wireless is set, the setting range will
be 1/1 to 1/128.
When a flash other than the EL-1 is used as a receiver, if a low flash firing level is
set, the correct firing level may not be displayed on the receiver side.
> or < > in Step 2, push the joystick
143
> to
> to set the flash output,