The Sigma EF-500 DG SUPER is designed to work with autofocus Nikon 35mm SLR and Digital SLR cameras for convenient, creative, and versatile flash photography. It has a powerful maximum guide number of 165 in feet (50 in meters) at 105mm focal length (ISO 100). The flash"s angle of illumination is automatically set to match your lens"focal length ranging from 28mm wide-angle to 105mm medium-telephoto. It also covers 17mm ultra-wide angle when used with the built-in diffuser. It enables full automatic flash photography with Nikon Autofocus SLR Cameras with TTL automatic flash exposure control. The Sigma EF-500 DG Super"s degree of electronic compatibility includes dedicated i-TTL flash photography with those Nikon cameras that offer this feature. For bounce flash it can be tilted 90-degrees upwards and 7-degrees downward for close-ups. Also it can be swiveled 180-degrees to the left and 90-degrees to the right. This versatility in bounce positioning provides you with a great degree of creativity in your flash photography. It also incorporates a "modeling flash" mode allowing you to preview where the shadows will fall on the subject. The EF-500 DG SUPER incorporates wireless TTL flash photography, slave flash photography, and FP flash photography (synchronized with high shutter speeds). In addition, manual flash also can be set at 8 output power levels. The covering focal length of the flash can be seen on the LCD panel, and a flash ready signal can be seen in the viewfinder. The EF-500 DG SUPER also incorporates an auto power off system. The flash uses readily available 4 x AA Alkaline or NiMH Rechargeable Batteries.