Canon EOS Rebel T5i 18-55mm IS STM Lens Kit Manual (en)

When you set the power switch to <k>, the [Z1/Z2] tab will show 
functions dedicated to movie shooting. The menu options are as 
[Z1] menu 
[Z2] menu
AF method
The AF methods are the same as described on pages 159-165. You 
can select [u+Tracking], [FlexiZone - Multi], or [FlexiZone - 
Movie Servo AF
The default setting is [Enable]. You can focus by pressing the 
shutter button halfway regardless of the setting.
• When [Enable] is set:
• You can shoot a movie while focusing a moving subject 
continuously. With certain lenses, the lens mechanical sound 
during focusing may be recorded. If this happens, use the 
Directional Stereo Microphone DM-E1 (sold separately) to reduce 
the lens mechanical sound in the movie. Using EF-S18-55mm f/
3.5-5.6 IS STM or EF-S18-135mm f/3.5-5.6 IS STM lens can 
minimize the focusing noise recorded during movie shooting.
• During Movie Servo AF, turn off the power before you set the 
lens’s focus mode switch to <MF>.
 Movie Menu Function Settings