The EF-500 DG SUPER is designed to work with Sigma 35mm SLR and Digital SLR cameras, for advanced flash photography. It has a maximum guide number of 165 in feet or 50 in meter at 105mm focal length (ISO 100). The projection angle of the flashlight is set automatically to match the lens" focal length ranging from 28mm wide-angle to 105mm medium-telephoto. It also incorporates a built-in diffuser that expands the angle of illumination down to that of 17mm lens. It enables full automatic flash photography by TTL automatic flash exposure control. It now includes STTL flash photography for Sigma cameras. For bounce flash it can be tilted 90° upwards and 7° downward for close-ups. Also it can be swiveled 180° to the left and 90° to the right. It incorporates "modeling flash" mode to provide proper light distribution to check the shadow of the subject. The multi pulse flash features enable reduced power setting from 1/4 to 1/128 in 6 steps and the pulse frequency of the flash can be set from 1Hz to 199Hz. 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 flashlight 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 auto power off system.