The newest addition to the Sigma line of flashes is the most powerful one yet now offeringGuide 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 inrange 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 bydegrees allowing ease of use for close-up photography. Among the advanced features of this flash ismodeling 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 confirmation ready light will be emitted.Specifications Guide Number:- 1/m (200/fit) ISO100/m Power Source:- our AA Alkaline or AA NiCd or Ni-MH Batteries Charging Time:- pproxSeconds (Alkalines) Approx.Seconds (NiCd Ni-MH) Number of Flashes:- pprox.120 Flashes (Alkaline) Approx. 160 flashes (Nicd Ni-MH) Illumination Angle:- 4mm to 105mm (17mm with the Built-In Wide Panel) Bounce:- p 0-90 Right 0-90 Left 0-180 Down 0-7 Dimensions:- .0in.5.5in.4.6 in. Weight:- 1.6 oz.Included Items Sigma EF-610 DG Super Flash Sigma 1-Year USA Warranty Sigma FS-11 Flash Stand Sigma Carrying Case.