Nikon Speedlight SB-400 is an external flash unit that provides i-TTL flash operation in a compact and lightweight body at an affordable price. The SB-400 offers a guide number of 30 (ISO 200, m), and effortless bounce flash function. The SB-400 is a flash unit for entry-level digital SLR users, but it is also useful for D2 series digital camera users as a handy flash unit.The SB-400 has been developed to provide an entry-level external flash unit, which is compatible with i-TTL flash operation. In combination with cameras compatible with Nikon Creative Lighting System the SB-400 is controlled in i-TTL and D40's M (manual) mode. Its flash head can be tilted in 4 steps, horizontal, 60, 75 and 90 degrees, and has a flash shooting distance range from 0.6m to 20m (depends on the ISO setting). Slow Sync, Red-eye Reduction and other flash modes can also be set on the camera body. With the SB-400, users can easily enjoy brighter and more natural lighting for better flash pictures.