Canon EOS-3 Instructions Manual page 99

Wireless Multi-Flash System
The Canon Speedlite 550EX has the following three features:
(1) E-TTL autoflash
(2) Slave unit
(3) Wireless master control of other slave-triggered 550EX units
By using the above features, you can set up a wireless E-TTL autoflash
system with up to three Speedlites. You can also set the flash output ratio
between the Speedlites to create the desired flash lighting effect.
• For details, see the 550EX and ST-E2's Instructions.
Wireless multi-flash system
Canon Speedlite
550EX
Flash Photography with Speedlite 550EX
Canon
Speedlite
Transmitter
ST-E2
Canon Speedlite
550EX
99