Electronic Flash Sigma EF-500 works with AF SLR cameras from all manufacturers with sophisticated flash photography. It has a maximum guide number of 50 setting at 105mm focal length (ISO 100m) / 165 ft (ISO100 ft). Projection angle of the flashlight is set automatically to match the focal lengths ranging from 28mm wide-angle to 105mm medium-telephoto. It incorporates a built-in wide angle diffuser that covers angle of view down to 17mm focal length. It enables full automatic flash photography by TTL automatic flash exposure control. It includes 3-D multi-sensor balanced fill flash function for Nikon. 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. In addition manual flash can be set to full and 1/16 output levels in 2 steps.