Canon EOS Rebel T5i Instruction Manual page 327

I cannot lock the focus and recompose the shot.
Set the AF operation to One-Shot AF. Focus lock is not possible in the
AI Servo AF and AI Focus AF operations (p.98).
With FlexiZone - Multi, it takes longer to autofocus.
Depending on the shooting conditions, it may take longer to focus the
subject. Use FlexiZone - Single instead or focus manually.
The continuous shooting speed is slow.
Depending on the lens type, shutter speed, aperture, subject
conditions, brightness, etc., the continuous shooting speed may
become slower.
The maximum burst during continuous shooting is lower.
With ISO 12800 or "H" (equivalent to ISO 25600), the maximum burst
for continuous shooting will greatly decrease (p.93).
Set [z3: High ISO speed NR] to [Standard/Low/Disable]. If it is set
to [High] or [Multi Shot Noise Reduction], the maximum burst during
continuous shooting will greatly decrease (p.126).
With [Chromatic aberration: Enable], the maximum burst for
continuous shooting will greatly decrease (p.130).
During WB bracketing, the maximum burst for continuous shooting will
decrease (p.140).
If you shoot something that has fine detail (such as a field of grass),
the file size will be larger and the actual maximum burst may be lower
than the number mentioned on page 89.
Troubleshooting Guide
327