Af Stop Button - Canon EF 400mm f/2.8L IS USM Instructions Manual

Switching the Focusing Distance Range
If you use AF from outside the specified focusing
distance range, the lens may stop focusing when it
reaches the limit of the range. This is not a
malfunction. If this occurs, press the shutter button
halfway down again.

4. AF Stop Button

During autofocus operation, you can press the
AF stop button to temporarily pause autofocus.
If the shutter button is still pressed halfway
when the AF stop button is released,
autofocusing will continue as before.
AF Stop Button
The AF stop function also works in AI Servo AF
mode.
●
With the EOS 630/600, RT, A2/A2E/5, or 10S/10
set to the AI Servo AF mode and continuous
shooting, AF will not resume even after you let
go of the AF stop button. Press the shutter
release button halfway to resume AF.
●
With the EOS A2/A2E/5 and 10S/10 set to the
Sports mode, AF will not resume even after you
let go of the AF stop button. Press the shutter
release button halfway to resume AF.
●
You can change the functions of the AF stop
button using the camera's Custom Function. For
details, please refer to the camera's instructions.
ENG-6