You should use fill flash outside because you don’t want your subject to look unrealistic due to a superfluous light. Don’t try to rival the sun instead try to complement the sun light by adjusting the intensity of the fill flash. Place the subject in a specific place so that the sun is behind the back of the subject. The sun will reflect more light on the hair and also catchlight on the eyes. You can use a reflector to ramp up the glow of the subject’s face. The reflector functions to bounce the flash or ambient light back onto the subject’s face. There are a number of occasions when using flash is not only pointless but also can wreck your image. Flash requires skill and experience to take advantage of the technique. It is because the intensity of the flash varies based on the presence of light no matter whether its natural or artificial light.