Setting The Focus Mode - Canon ULTRASONIC EF400mm f/2.8L IS III USM Instructions Manual

3. Setting the Focus Mode

To shoot in autofocus (AF) mode, set the focus
mode switch to AF.
To use only manual focusing (MF), set the focus
mode switch to MF, and focus by turning the
focusing ring.
See p. 14 for information on power focus (PF).
Focusing ring
Focus mode switch
Quickly turning the focusing ring may result in
O O
delayed focus.
The lens' focusing ring is electronic.
O O
When AF operation is set to [ONE SHOT],
O O
manual focus is possible after autofocusing
has been completed by continuing to press the
shutter button halfway (Full-time manual focus).
There are times when camera setting changes
are required.
When the AF button assignment is changed from
O O
the "shutter button" (using the camera's Custom
Function), manual focus is always possible
regardless if the shutter button is pressed
halfway any time the lens is not autofocusing.
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