This Sigma EF610 DG ST Flash for Pentax is a powerful (guide number of 61) shoe mount flash designed for use with Pentax SLR cameras. TTL automatic flash exposure control is available for all compatible cameras. An auto zoom function automatically sets the optimum illumination angle according to the focal length in use (from 24mm to 105mm), or with the built-in wide panel, 17mm.
The flash head can be tilted up and to the right by 90 degrees, to the left 180 degrees for flexibility in using bounce flash, or down by 7 degrees for close-up photography. There's also a manual flash mode, making it possible to set the flash power to full or 1/16 power. A confirmation light keeps you informed as to when the flash is fully recycled, and there's an Auto Power-Off function to help save battery power.