Fill flash is a method in photography where the camera flash is employed to brighten up the shadows in a picture. This technique is particularly beneficial when the main subject is not well-lit due to insufficient natural light. Fill flash can come in handy during sunny days when the sunlight is too harsh. By mastering this technique, you can effectively use fill flash to enhance the details in the foreground of landscape shots. Fill flash has the potential to enhance various types of photography, including portraits, macro, and landscapes.