How To : Slamming Fill Flash
For really striking outdoor portraits, give this a shot. Get your subject into shadow or crouch down beneath them. Aim your camera at the sky and take a reading. Recompose your shot and shoot your subject with a burst of flash light. The result: bare, instant glamour!
Outside of this techinque, metering for the sky is often a good idea for digital images. If you notice that your sky is always white, even on a beautiful day, it’s because your camera is metering off a relatively dark subject and thereby horribly overexposing the sky. Try aiming for the sky, recomposing, and focusing. If it’s nice out, you’ll get blue every time. If you subject comes out really dark, just bust out the flash.