Canon EOS REBEL T5I Instruction Manual page 72

_H_ Cautions when [Movie servo AF] is set to [Enable]
Shooting Conditions that Make Focusing Difficult
A fast-moving subject approaching or moving away from the camera.
A subject moving at a close distance in front of tne camera.
/¢ Also refer to "Shooting conditions that make focusing difficult" on page
165.
o Since using Movie Servo AF will consume battery power, the number of
possible shots and the possible movie shooting time will be reduced.
- During zooming or image magnification. Movie Servo AF operation will be
stopped momentarily.
- During movie shooting, if a subject approaches / moves away, or if
the camera is moved vertically or horizontally (panning), the
recorded movie image may momentarily expand or contract (change
in image magnification).
202