Canon EOS rebel xs - Manual (Page 158)

3 Custom Function SettingsN
158
C.Fn IV: Operation/Others
C.Fn-9 Shutter/AE lock button
0: AF/AE lock
1: AE lock/AF
Convenient when you want to focus and meter separately. Press the
button to autofocus and press the shutter button halfway to attain
AE lock.
2: AF/AF lock, no AE lock
In the AI Servo AF mode, you can press the button to stop the AF
operation momentarily. This prevents the AF from being thrown off by
any obstacle passing between the camera and subject. The exposure is
set at the moment the picture is taken.
3: AE/AF, no AE lock
This is useful for subjects which keep moving and stopping repeatedly.
In the AI Servo AF mode, you can press the button to start or stop
the AI Servo AF operation. The exposure is set at the moment the
picture is taken. Thus, the optimum focusing and exposure will always
be achieved as you wait for the decisive moment.
C.Fn-10 SET button when shooting
You can assign a frequently-used function to <0>. When the camera is
ready to shoot, you can press <0>.
0: LCD monitor On/Off
Gives the same function as the button.
1: Change quality
After pressing <0>, look at the LCD monitor and press the key to
set the image-recording quality directly.
2: Flash exposure compensation
When you press <0>, the flash exposure compensation screen
appears so you can quickly change the setting.
3: Menu display
Gives the same function as the button.
4: Disabled