A Ae Lock; Ae Lock Effects - Canon Rebel T2i EOS 550D Instruction Manual

A AE LockN
Use AE lock when the area of focus is to be different from the exposure
metering area or when you want to take multiple shots at the same exposure
setting. Press the <A> button to lock the exposure, then recompose and take
the shot. This is called AE lock. It is effective for backlit subjects.

AE Lock Effects

Metering
Mode
(p.86)
AE lock is applied at the AF
q *
point that achieved focus.
AE lock is applied at the center AF point.
wre
* When the lens' focus mode switch is set to <MF>, AE lock is applied at the center AF point.
Focus the subject.
1
Press the shutter button halfway.
The exposure setting will be
displayed.
Press the <A> button.
2
The <A> icon lights in the viewfinder
to indicate that the exposure setting is
locked (AE lock).
Each time you press the <A> button,
it locks the current auto exposure
setting.
Recompose and take the picture.
3
If you want to maintain the AE lock
while taking more shots, hold down
the <A> button and press the shutter
button to take another shot.
AF Point Selection Method (p.68)
Automatic Selection Manual Selection
AE lock is applied at the
selected AF point.
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