Canon EOS Rebel T7 Manual De Instrucciones Básicas página 67

During Live View shooting, it may be difficult to focus on dots of light such as
in a night scene. In such a case, it is recommended that you set the AF
method to [Quick mode] and shoot. If it is still difficult to focus, set the lens's
focus mode switch to <MF> and focus manually.
Tell the subject to keep still even after the flash fires.
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If you use the self-timer together with flash, the self-timer lamp will light
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up briefly after the picture is taken.
6 Shooting Night Portraits
65