When you want to fire the flash every shot.
In the Flash mode, the flash fires regardless of
available light. For example, this mode can be used to
brighten up a subject's shaded face or under artificial
lighting such as back-lit, fluorescent light. Use this
mode within the flash working range (p. 35).
It may be hard to work under excessively bright light.
Closing the lens barrier returns to Auto.
FILL-IN FLASH (Forced Activation)
38