Canon 40D - Manual (Page 114)

114
Live View ShootingN
If the [8C.Fn III -6] (AF during Live View shooting) setting is set to
[Enable], you can focus with the
button.
Be sure to set the lens focus mode switch to <f>, set the AF
mode to <X>, and select the center AF point.
1
Press <0> to the display Live
View image.
2
Focus the subject.
Cover the subject with the focusing
frame and press the
button.
X The Live View image will turn off, the
reflex mirror will go back down, and
AF will be executed.
X When focus is achieved, the beeper
will sound.
3
Return to the Live View image
display and shoot.
When you let go of the
button, the Live View image will
return.
Check the focus and press the
shutter button to take the picture.
Using AF to Focus
For very precise focusing, mount the camera on a tripod and magnify the
picture. Then focus manually. (p.110)
You can also use AI Servo AF or automatic/manual AF point selection.
However, if the AF point doesn’t cover the subject, you might not obtain
the desired focusing result.
You cannot take a picture during autofocusing. Take the picture only
while the Live View image is displayed.
The exposure will be set with focusing frame-linked evaluative metering.
(The metering cannot be linked with an AF point.)