Canon EOS60D18135ISKIT User Manual (en)

To shoot someone at night and obtain a natural-looking exposure in the 
background, use the <6> (Night Portrait) mode.
Use a wide-angle lens and a tripod.
When using a zoom lens, use the wide-angle end to obtain a wide 
night view. Also, use a tripod to prevent camera shake.
Keep the person within 5 meters/16.4 feet from the camera.
Under low light, the built-in flash will fire automatically to obtain a 
good exposure of the person. The effective distance of the built-in 
flash is 5 meters/16.4 feet from the camera.
Shoot also with <1> (Full Auto).
Since camera shake is prone to occur with night shots, shooting also 
with <1> (Full Auto) is recommended.
6 Shooting Portraits at Night
Shooting Tips
Tell the subject to keep still even after the flash fires.
If the self-timer is also used, the self-timer lamp will light briefly when the 
picture is taken.