Nikon SB-900 AF Speedlight

The SB-900 can work as a stand-alone flash, or as part of a wireless group, either in Commander mode or as a slave (remote). The i-TTL system in this flash supports Advanced Wireless Lighting and versatile functions for up to four groups of Speedlights, with 3 remote i-TTL Speedlight groups controlled through the master SB-900. i-TTL Balanced Fill-Flash flash control employs Nikon's Advanced Data Communication system. This system provides an improved method for the monitor pre-flash and wireless operation that marks an evolution in higher precision over Nikon's acclaimed D-TTL Balanced Fill-Flash control system, and forms the core of the Creative Lighting System.