The Nikon SB-400 is a compact external flash designed for Nikon cameras with i-TTL hot-shoe compatibility, ideal for photographers seeking high-quality lighting in a lightweight, portable unit. It features a guide number of 21 (ISO 100, 35mm) and supports i-TTL automatic exposure control for accurate and consistent results. The tilt head, adjustable up to 90° upward, enables bounce flash techniques to produce soft, natural lighting — perfect for portraits and indoor photography. The flash coverage is optimized for lenses up to 18mm (DX format), ensuring even light distribution across the frame. With a recycle time of 2.5–4 seconds powered by two AA batteries, and a weight of just 127 g, it is extremely convenient for everyday use or travel. Its solid build and straightforward operation make it an excellent choice for both enthusiasts and professionals looking for a compact yet capable secondary flash unit.