I am currently working with flash and trying to understand more about it. For these photos, I am using an external flash which allows me to try placing the flash in different positions. The first photo above is without any type of flash at all. Ambient light only. In the second picture, the flash is positioned on the camera's hot shoe, pointing directly at Sam, my willing and faithful model. Even though it has been powered down quite a bit, it still creates harsh shadows. The big difference between a pop-up and external flash is flexibility. In the last photo, I have the flash positioned about two feet behind the camera and aimed almost vertically upward. The light hit a reflector I was holding and bounced downward. The light filled in the dark background and any harsh shadows became softer. The result? An almost correctly exposed image. Flash can be a very useful tool if used effectively. 

All photos were taken with an ISO of 200, a shutter speed of 1/200, and an aperture of f/9.