What is the purpose of an external flash?

An external flash serves the primary purpose of providing additional light in low-light situations, which is essential for achieving well-exposed photographs. When ambient lighting is insufficient, an external flash can illuminate the subject, allowing for clearer and sharper images without the negative effects often associated with high ISO settings, such as noise.

Using an external flash can also enhance creative control over lighting. Photographers can manipulate light direction, intensity, and diffusion, enabling them to achieve desired effects like soft shadows or highlights. This versatility is especially beneficial in scenarios where the natural light is inadequate or when trying to capture motion in darker environments.

The other options are not functions of an external flash: improving zoom capabilities is related to the camera's lens, stabilizing the camera usually involves a tripod or in-camera stabilization systems, and adjusting white balance is typically handled through the camera's settings and not directly affected by the use of a flash.