The newest addition to the Sigma line of flashes is the most powerful one yet, now offering a Guide number of 61 which translates into 61/m (200/ft) and designed to work with the latest TTL auto exposure systems of all the most popular digital and film SLR cameras. Advanced features and high performance allows photographers to express their intentions accurately. The EF-610 DG SUPER's auto zoom function automatically sets the optimum illumination angle in accordance with the lens' focal length in a range from 24mm to 105mm. When the built-in Wide Panel is used, the flash can cover an angle of 17mm. For bounce flash the flashgun head can be tilted up by 90 degrees, to the left by 180 degrees, or to the right by 90 degrees. It can also be tilted down by 7 degrees allowing ease of use for close-up photography. Among the advanced features of this flash is a modeling flash function, multi-pulse flash, TTL wireless flash, FP (high speed) flash, rear-curtain Synchro flash and manual flash mode, which allows the photographer to set the flash power level by up to eight stops. The Auto Power-Off function automatically shuts off the LCD panel to help save battery power. When the flash gun is fully charged, a confirmation "ready' light will be emitted.SpecificationsGuide Number: 61/m (200/fit) ISO100/mPower Source: Four AA Alkaline or AA NiCd or Ni-MH BatteriesCharging Time: Approx 7 Seconds (Alkalines) Approx. 5 Seconds (NiCd, Ni-MH)Number of Flashes: Approx.120 Flashes (Alkaline) Approx. 160 flashes (Nicd, Ni-MH)Illumination Angle: 24mm to 105mm (17mm with the Built-In Wide Panel)Bounce: Up 0-90, Right 0-90, Left 0-180, Down 0-7Dimensions: 3.0in. X 5.5in. X 4.6 in.Weight: 11.6 oz.Included ItemsSigma EF-610 DG Super Flash Sigma FS-11 Flash StandSigma Carrying Case.