The Sigma EF 610 DG Super Flashgun Nikon fit flashgun features a powerful Guide Number of 61 and is designed to work with the latest TTL auto exposure systems of all popular digital and film SLR cameras. The 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.