The SB-700 Speedlight Shoe Mount Flash from Nikonis an on-camera flash, designed for use with Nikon DSLR cameras that use the i-TTL metering system. It is compatible with DX and FX sensors, and its power zoom head covers a 24-120mm range when used with an FX camera.
The Nikon SB-400 Speedlight is an intelligent and versatile external flash unit that provides i-TTL flash operation in a super-compact and ultra-lightweight body at an affordable price. Designed as an entry-level external flash, this flash is ideal for the compact D-40 digital SLR camera, but it is also useful for hobbyists and professionals looking for a handy i-TTL flash unit offering an effortless bounce flash function. When combined with cameras that are compatible with the Nikon Creative Lighting System, the SB-400 is controlled in i-TTL and D40's M (manual) mode.