Canon EOS 450D - Manual (Page 102)

102
Under [7 Custom Functions (C.Fn)],
when [AF during Live View shooting]
(p.157) is set to [1: Quick mode] or [2: Live
mode], you can focus with AF. Quick mode
and Live mode use a different AF method.
If you want precise focusing, magnify the
image and focus manually. (p.98)
This is the same as using AF (p.60, 61) as usual with the dedicated AF
sensor. Although you can focus the desired area quickly, the Live View
image will be interrupted momentarily during the AF operation.
Set to Quick mode, the lens focus mode switch to <f>, and the
AF mode to <X>.
1
Select the AF point for focusing.
Before starting Live View shooting,
select the AF point.
Press the button and press the
key to select the AF point.
Press the shutter button halfway for
shooting ready.
2
Display the Live View image.
Press <0>.
X The Live View image will appear on
the LCD monitor.
The selected AF point will be
displayed.
The focusing frame (larger frame) will
also be displayed.
Using AF to FocusN
C.Fn-8-1: Quick mode