Canon Speedlite 580EX II Instruction Manual page 39

Indoors
Outdoors
Use the mini stand (tripod socket provided) to prop up the slave unit.
Use the bounce feature to swing the slave unit so that its wireless
sensor faces the master unit.
Indoors, the wireless signal can also bounce off the wall so there is
more leeway in positioning the slave unit(s).
After positioning the slave unit(s), be sure to test the wireless flash
operation before shooting.
Do not place any obstacles between the master unit and slave
unit(s). Obstacles can block the transmission of wireless signals.
38
Check the flash operation.
7
Press the master unit's test firing
button.
The slave unit will fire. If the flash
does not fire, adjust the slave unit's
angle toward the master unit and
distance from the master unit.
Set the camera and shoot.
8
Set the camera in the same way as
with normal flash shooting.
10m (32.8ft.)
o
80
8m (26.2ft.)
15m (49.2ft.)
12m (39.4ft.)