An external flash is a portable lighting device used in photography to enhance illumination when taking pictures. Unlike built-in camera flashes, external flashes can be mounted on the camera or used off-camera, providing greater flexibility and control over lighting conditions. They often have adjustable power settings and can be tilted or rotated to create different lighting effects. External flashes are particularly useful in low-light situations or when capturing subjects in shadow. They help reduce harsh shadows and improve the overall quality of images. Photographers can also use external flashes in combination with modifiers, such as softboxes or umbrellas, to achieve softer, more diffused lighting.