When should I use flash?

I always surprise my photography classes by suggesting that an important time to use flash is when taking photos of people in bright sunlight.  Huh! Bright sunlight creates harsh shadow on the face. Most cameras when the flash is fired in bright sunlight act as fill flash. A small built in flash cannot over power the sun and become the main light, but it can fill in shadows.

Here is a photo of a young friend sitting in mottled sunlight. The light was very uneven and the shadows were not pleasant. I merely turned on the flash and presto. A pleasing portrait of the girl. A pair of photos below show another example of fill flash. In the first photo the flash was not fired. In order to show a little detail in the foreground, the sky is slightly over exposed. In the second image the flash lit the tree in the foreground and allow the sky to be exposed less and therefore show more rich color.

The bottom line here is: Just because there is plenty of light doesn't mean there is no reason to use a flash. Think of it as a way to even things out. With people lighten shadows. Or if a person is lit by the sun from the back, your flash can add light to their front and even things out. In the tree shot most of the light is in the sky in back of the tree and the flash again evens things out by adding light to the tree front.