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