Canon Speedlite 580EX II Instruction Manual page 47

Setting Manual Flash and Stroboscopic Flash with the Slave
Manual flash or stroboscopic flash can be set manually with the slave
unit. As with studio flash units, you can set the flash output individual
with the slave units for wireless or manual flash.
b n u a l Flash
Hold down the
<MODE>
button f o ~
sec, or more.
b
<M>
will blink.
Set the manual flash output (p.22).
Hold down the
<MODE>
button
Fc
2 sec. or more.
b
<M>
will blink.
Press the
<MODE>
button again
and
<MULTI>
will blink.
Set the stroboscopic flash (p.24).