The SB-900 i-TTL Speedlight leads the Nikon Creative Lighting System delivering the portability, power and versatility to support any photographer’s creative lighting imagination. FEATURES: Nikon’s Flagship Creative Lighting System Speedlight: Powerful and versatile SB-900 works as a stand-alone flash, featuring wireless operation as a Commander or wireless remote light source. Control up to three remote Speedlight groups and an unlimited number of compatible Speedlights: The SB-900"s Wireless Commander Mode offers wireless control at the master Speedlight position. Four wireless channel options allow you to manage wireless conflicts in multiple photographer environments. Streamlined controls and menus: The Rotary Select Dial sets key flash functions quickly—a prominent Master and Remote control switch simplifies wireless operation. FX/DX format identification: Automatic FX/DX switching optimizes light distribution angle. Expanded Auto Power Zoom Coverage: The SB-900 provides zoom coverage from 17-200mm in the FX-format and 12-200mm coverage in the DX-format. Choose from 3 light distribution patterns: Improve light quality by selecting Standard for general illumination, Center-weighted for portraits, or Even for groups or interiors. User-friendly firmware updating: Allows uploading of performance enhancement developments to the SB-900 with select Nikon digital SLR cameras Color gel filter identification: The SB-900 automatically identifies mounted color gel filters and adjusts the camera’s auto white-balance setting with select Nikon digital SLR cameras. Flash Tube Overheat Protection: An added m