Canon EOS Rebel T4i 18-135mm IS STM Lens Kit Instruction Manual page 105

Shooting Tips
If the subject is far away, increase the ISO speed (p.90).
By increasing the ISO speed, you can extend the flash range.
In bright light, decrease the ISO speed.
If the exposure setting in the viewfinder blinks, decrease the ISO speed.
Detach the lens hood and keep at least 1 meter/3.3 feet away
from the subject.
If the lens has a hood attached or you are too close to the subject,
the bottom of the picture may look dark due to the obstructed flash.
For important shots, check the image on the LCD monitor to make
sure the flash exposure looks natural (not dark at the bottom).
3 Red-eye Reduction
Using the red-eye reduction lamp before taking a flash picture can
reduce red eye.
Red-eye reduction will function in any shooting mode except <7>,
<3>, <5>, or <G>.
The red-eye reduction feature is most effective when the subject looks at
the red-eye reduction lamp, when the room is well lit, or when you are
close to the subject.
When you press the shutter button halfway, the
scale display on the bottom of the viewfinder will
shrink and turn off. For best results, take the picture
after this scale display turns off.
The effectiveness of red-eye reduction varies depending on the subject.
Under the [z1] tab, select [Red-eye
reduc.], then press <0>. Select
[Enable], then press <0>.
For flash photography, when you press
the shutter button halfway, the red-eye
reduction lamp will light up. Then when
you press the shutter button
completely, the picture will be taken.
D Using the Built-in Flash
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