Modeling Flash - Canon Speedlite 580EX II Manual

If <yl> is set, the slave unit in slave group <3> will not fire.
If you point the slave unit in slave group <3> toward the subject, the
subject will be overexposed.

Modeling Flash

If the camera has a depth-of-field preview button, pressing it will fire the
flash continuously for 1 sec. This is called the modeling flash.
It enables you to see the shadow effects on the subject and the lighting
balance. You can fire the modeling flash for both wireless and normal
flash shooting.
Do not fire the modeling flash more than 10 consecutive times. If you
fire the modeling flash 10 consecutive times, allow the Speedlite to
rest for at least 10 min. to avoid overheating and deteriorating the flash
head.
The modeling flash cannot be fired with the EOS REBEL 2000/300 and
Type-B cameras (p.2).
About Slave Group Control
Slave group A
ID = A ID = A
44
Set the master unit and shoot.
2
For example, if you have the slave ID set
to <1> for three slave units, all three
slave units will be controlled as if they
were one Speedlite in slave group A.
ID = A
Follow "Setting the Master Unit and
Shooting" on page 42. In step 4,
select <k>.