Test Flash And Modeling Flash With A Slave Unit - Canon Speedlite 430EXIII-RT Instruction Manual

While the flash mode can be set to </> auto external flash metering
when 430EX III-RT is set as a master unit, this function is effective when
using a slave unit that supports </> (example: 600EX-RT).
430EX III-RT does not support </>. As a result, when the flash
mode of the master unit is set to </>, 430EX III-RT units set as the
slaves do not fire. When using 430EX III-RT as a slave and setting the
flash mode with the master, do not set the flash mode to </>.
When 430EX III-RT is set as the master unit and the flash mode of firing
group "A" is set to </>, master flash firing is not performed even if
430EX III-RT is set to "Master flash firing: ON" (p.53).
When the flash mode is set to <a> or </>, exposure is
controlled as a single group to obtain the standard exposure for the main
subject. If you shoot with multiple firing groups pointing toward the main
subject, overexposure may result.
For </>, refer to the instruction manual of a Speedlite compatible
with auto external flash metering.
When you do not want a certain group to fire, select <E> when
setting the flash mode in step 3.
The order of firing among firing groups does not need to be consecutive;
for example, A, C, E can be set.
You can set the flash output or flash exposure compensation amount by
simply pressing <8>, selecting the firing group using the <S> cross
keys, and turning <9> (P.Fn-08/p.88).

Test Flash and Modeling Flash with a Slave Unit

In radio transmission wireless shooting, you can fire the test flash and
modeling flash (p.36) from a 430EX III-RT set as a slave unit.
Test Flash and Modeling Flash with a Slave Unit
Select <N> or <M>.
Press <8> of the slave unit.
Turn <9> to select <N> or
<M>, then press <8>.
A flash signal is sent from the slave unit
to the master unit, and a wireless system
test flash or modeling flash is fired.
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