Changing the Autofocus Mode
Focus the subject.
Aim the AF points over the subject and press the shutter button halfway. The Live View image will turn off, the reflex mirror will go back down, and AF will be executed.
When focus is achieved, the AF point which achieved focus will turn green and the Live View image will reappear.
If focus is not achieved, the AF point will turn orange and blink.
Take the picture.
Check the focus and exposure, then press the shutter button completely to take the picture (p.122).
You cannot take a picture during autofocusing. Take the picture while the Live View image is displayed.