Instructions
Remove headgear or clothing that covers the subject's face, even partially, in shade. If you take a photo in direct sunlight, and your subject's face is obscured, it will be underexposed. Ensure that, if headgear is essential, the peak or front part is folded upwards, or situated in such a way that the entire face can be lit by the fill-in flash.
Take advantage of fading light, such as just before or at sunset, to create a surreal, often dramatic effect. The fill-in flash will light up the subject's face while maintaining the natural light of dusk in the background. If the flash is not too overpowering (this is a particular risk if you are using an external flash), the subject's skin tones should be soft, giving her a serene appearance.
Consult the camera's or external flash's instruction manual for the fill-in flash's operational distance. Each camera or external flash will operate only within a specified distance. Beyond this distance, the flash may fail to provide light. However, external flashes can usually be manipulated to fire at close and far ranges, within a certain limit.
Analyze your subject's background. A dark background will increase the risk of overexposing their face, as it may contrast harshly with the lighting produced by the flash. Shooting in a more subtle or color neutral background, such as a softly lit meadow or a honey-colored building, may result in an aesthetically pleasing image that will place your subject's skin tone in the best light.
Change the aperture settings on your camera for a more pleasing background, or a faster shutter speed. By using your fill-in flash with a larger aperture of f2.8, you will soften and blur your background, which will, in turn, emphasize your subject's face. If your shutter speed is too slow, which can result in blurred photos, a larger aperture will increase it.
Note fluctuations to your fill-in flash as a result of amending settings; a large aperture, for instance, will result in less flash exposure, and vice versa.