Why doesn't the camera light flash?

Common flash that can't be used well is as follows:

1, the flash index of most flashlights is adjustable, that is, the brightness is adjustable. Many people don't know this. If the flash is too strong, there will be obvious shadows;

2. The working distance of the flash is four or five meters, which many people don't know. Anyway, it is useless to use the flash. For example, in sports competitions or stage performances, you often see a flash, which actually has no effect. Because the distance is too far;

3, shooting portraits in the sun, in fact, is to use a flash, its role is to fill the light, to avoid too strong contrast between black and white faces.