Canon EOS 5D - Manual (Page 101)

101
Flash Photography
• E-TTL II Wireless Autoflash with Multiple Speedlites
Like with wired, multiple Speedlites, E-TTL II wireless autoflash with multiple
Speedlites provides all the above features. Since connection cords are
unnecessary, flexible and sophisticated lighting setups are possible. (Only with
wireless-compatible Speedlites.)
With TTL and A-TTL autoflash Speedlites (EZ-, E-, EG-, ML-, TL-
series) set in the TTL or A-TTL autoflash mode, the flash will be fired
only at full output. If you set the camera’s shooting mode to manual
or aperture-priority AE, you can adjust the aperture and fire the flash
at full output. Meanwhile, the Speedlite will remain in the TTL or A-
TTL autoflash mode.
When the 580EX or 550EX is set to C.Fn-03-1, the flash will always
be fired at full output even in the TTL autoflash mode.
TTL and A-TTL Autoflash Speedlites