Other Settings; Fe Lock - Canon EOS 600D Instruction Manual

Other Settings
Flash Exposure Compensation
When [Flash mode] is set to [E-TTL II], flash exposure compensation
can be set. The flash exposure compensation settings (see below)
which can be set will differ depending on the [Wireless func.] and
[Firing group] settings.
[Flash exp. comp]
_ The flash exposure compensation is
applied to the built-in flash and all
external Speedlites.
[--,_ exp. comp.]
_ The flash exposure compensation is
applied to the built-in flash.
[_ exp. comp.]
_ The flash exposure compensation is
applied to all external Speedlites.
[A,B exp. comp.]
_ The flash exposure compensation is
applied to both groups A and B.
FE Lock
If [Flash mode] is set to [E-TTL II], you can press the <=X-> button to
perform FE lock.
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