Using High-Speed Sync (HSS) flash during the day is a powerful way to eliminate harsh shadows caused by direct sunlight, especially around noon. Start by exposing for the ambient light first—set a fast shutter speed to control the bright background while keeping your aperture where you want it for depth of field. Once the ambient exposure looks slightly underexposed, enable HSS on your flash and add light to your subject to fill in deep eye sockets and hard facial shadows. Position the flash slightly off-axis or raised above eye level to keep the light natural, and adjust flash power until the subject blends seamlessly with the scene. The key is balance: the sun becomes your rim or background light, while the HSS flash acts as soft fill, giving you clean, evenly lit images without the harsh, contrasty shadows that daylight alone creates.