If you're a sports, news or events pro or shoot hard, hot and heavy, you'll love the Nikon SB-910. The SB910 keeps belting out loads of light quickly. This isn't a classic Vivitar 285; the SB-910 recycles fast even at full power from 4 AAs. Fully compatible with Nikon Creative Lighting System Three illumination patterns (standard/even/center-weighted), with increased light distribution accuracy, are available to match every shooting environment Automatically detects Nikon FX and Nikon DX formats and selects suitable light distribution angles Power zoom function covers wide 17-200 mm (in FX format) or 12-200 mm (in DX format) zoom ranges AF-assist illumination, compatible with multi-point AF system, covers wide 17-135 mm focal length range New MENU button enables quick access to custom settings, while improved LCD panel GUI (graphical user interface) enhances operability Durable and heat-resistant, easy-to-use, hard-type color filters (fluorescent or incandescent) included Automatically detects color filter types and transmits filter information to camera for optimum white balance setting Guide number: 34/111.5 (m/ft.) at 35 mm and 53/173.9 (m/ft.) at 200 mm (FX-format, standard illumination pattern, ISO 100, 20°C/68°F) Minimum recycling time: approx. 2.3 seconds with Ni-MH batteries Automatically detects increases in flash head temperature and controls recycling time accordingly, thus preventing overheating Firmware updates via Nikon digital SLR cameras Compatible with High-Performance Battery Pack SD-9 and Power Bracket Unit SK-6/6A Optional Water Guards WG-AS1 (for D3 se