Canon EOS Rebel T4i 18-135mm IS STM Lens Kit Instruction Manual page 157

Changing the Autofocus Method (AF Method)
Move the AF point.
2
Press the <S> key to move the AF
point to where you want to focus. (It
cannot go to the edges of the picture.)
To return the AF point to the center,
press <0> or the <L> button.
You can also tap the LCD monitor
screen to move the AF point.
Focus the subject.
3
Aim the AF point over the subject and
press the shutter button halfway.
When focus is achieved, the AF point
will turn green and the beeper will
sound.
If focus is not achieved, the AF point
will turn orange.
Take the picture.
4
Check the focus and exposure, then
press the shutter button completely to
take the picture (p.144).
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