An external flash is a portable lighting device used in photography to provide additional light when capturing images. Unlike built-in camera flashes, external flashes can be mounted on the camera or used off-camera, allowing for more creative lighting options. They often have adjustable power settings and can be tilted or rotated to bounce light off surfaces, creating softer and more flattering illumination. External flashes are commonly used in various photography settings, including portrait, event, and product photography. They can help reduce harsh shadows and improve image quality in low-light conditions. Many photographers prefer external flashes for their versatility and ability to enhance the overall look of their photos.