Canon EOS Rebel XT - Manual (Page 71)

71
f Selecting the AF ModeN
Pressing the shutter button
halfway activates the autofocus
and achieves focus once.
s The dot < . > inside the AF point
achieving focus flashes briefly in red.
Also, the focus confirmation light
<
o> in the viewfinder lights.
s With evaluative metering, the exposure setting
(shutter speed and aperture) will also be set
when focus is achieved. The exposure setting
and focus will be locked as long as the shutter
button is pressed halfway. (p.75) You can then
recompose the shot while retaining the
exposure setting and point of focus.
While you press the shutter
button halfway, the camera
focuses continuously.
¡ This AF mode is for moving subjects when
the focusing distance keeps changing.
s With predictive AF*, the camera can also
focus track a subject which steadily
approaches or retreats from the camera.
s The exposure is set at the moment
the picture is taken.
One-Shot AF for Still Subjects
AF point Focus
confirmation
light
AI Servo AF for Moving Subjects
If focus cannot be achieved, the focus confirmation light <
o> in the viewfinder will blink. If this
occurs, a picture cannot be taken even if the shutter button is pressed fully. Recompose the
picture and try and focus again. Or see “When Autofocus Fails (Manual Focusing)” (p.76).
In a Creative Zone mode (except <
8>), the beeper will not sound even when
focus is achieved. Also, the focus confirmation light <
o> in the viewfinder will not light.