The EF-530 DG ST flash from Sigma is designed to work with the latest traditional and digital camera TTL systems. It features a powerful number guide of 53 and sets itself automatically according to the lens? focal length within a range from 24mm to 105mm. When the built-in angle widener is used, the EF-530 DG ST can cover the viewing angle of a 17mm focal length. The head can be tilted up by 90, to the left by 180 or to the right by 90. It can also be tilted down by 7, allowing for ease of use for close up photography. In addition to its automatic mode, the EF-530 DG ST has a manual flash mode, making it possible to set the flash power level to full or 1/16. When the flash is fully charged, a confirmation light will light up and the flash exposure level can be checked through the camera?s viewfinder. The EF-530 DG ST also comes with an Auto Power Off function that helps save on battery power. This flash works with 4 batteries or AA rechargeable batteries (not included).