The focusable optical system of The DLH4 allows the light efficiency in its spot position to be 18 % higher than a traditional Fresnel design (usually capable of only an increase of 6% when focused). The DLH4 technology provides a clean beam without stray light as usually found in Fresnel lights. This light offers very even distribution within the beam compared to hot spots as produced by Fresnel studio lights. This latest version incorporates stunning aspherical mirror technology optics, drastically improved light output and the versatility of many power options to suit many different applications

The now classic DLH4 light head is the fourth generation release of this Oscar winning technology. The "focus head" Pre–collects light from the lamp and reflector allowing the use of a much smaller front lens and thus enabling the construction of a remarkably small light head capable of light output comparable to much larger light sources.