Canon EOS REBEL T2I Instruction Manual page 19

E×temal SpeedJites
EOS-dedicated, EX=series 8peediites
Basically operates like a built-in flash for easy operation,
When an EX=sedes SpeedHte (sold separately) is attached to the
camera, almost all the autoflash control is done by the camera, in other
words, it is like a high=output flash attached externally in place of the
built=in flash,
For detailed instructions, see the EX-series Speed[ite's instruction
manual, TMs camera is a Type=A camera that can use all the features
of EXosedes Speedlites=
Shoe-mount Speedlites Macro Lites
_ W th an EX-series Speed [e not compatible with flash function settLngs
(p.147), only [[=lash exp. comp] and [E=TTL [1 meter,] can be se_for
[External flash rune. setting]. (Certain EX-serles Speed[ites alsc
enable [Shutter sync.] to be set.)
Ufflash exposure compensation is set with the ex[ernal Speediite, the
flash exposure compensation {con dlsDayed on the camera's LCD
monitor wd[ change from [_ to 3%
_, If the flash metering mode is set to TTL autoflash with the Speedlite's
Custom Function, the flash will fire at full outpu_ only.
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