Canon EOS Rebel T1i Instruction Manual page 141

Flash exposure compensation
See "y Flash Exposure Compensation" on page 85.
E-TTL II
For normal flash exposures, set it to [Evaluative].
If [Average] is set, the flash exposure will be averaged for the entire
metered scene as with an external metering flash. Flash exposure
compensation may be necessary depending on the scene, so this
setting is for advanced users.
Clear Speedlite settings
On the [External flash func. setting] screen, press the <B>
button to display the screen to clear the flash settings. When you
select [OK], the settings for the built-in flash and external Speedlite
will be cleared.
Setting the External Speedlite Custom Functions
Display the Custom Function.
1
Select [External flash C.Fn setting],
then press <0>.
Set the Custom Function.
2
Press the <U> key, then press
<0>.
To clear all the Custom Function
settings, select [Clear ext. flash C.Fn
set.] in step 1.
3 Setting the FlashN
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