This PRO ND4/ND8/ ND16 filter reduce the amount of light entering the lens so wider apertures can be selected, which is perfect for portraiture to reduce depth of field. Subject appears crisp and clear while the background becomes a soft blur. Also widely used for photographs of waterfalls and other nature scenes to emphasise movement. The ND4 reduces light entering the camera lens by the equivalent of 2 stops. This medium-class ?lter series was developed in the mid-2000s when digital single-lens re?ex cameras were popular. Adopting digital multi-coat technology, these ?lters achieve an overall ?lter transparency of 99% (protector) with a minimum pricing premium. The ne.w-concept ?lter series employs a black-painted frame for reduced re?ection in the glass, a knurled frame for easy attachment, and other user-friendly features. These ?lters function well not only with digital cameras but also with ?lm cameras. Digital Multi-Coated Digital multi-coated filters greatly reduce the appearance of lens flare and ghosting caused by reflections. Black Almite Frame Filters feature a black matte aluminium satin finish almite frame which reduces reflections. Black Rimmed Glass These filters are equipped with black rimmed glass to reduce the chance of light reflecting off the edge. Low Profile Frame Ultra thin filter frames to help avoid vignetting on super wide angle lenses are also designed to hold a lens cap. Knurling Edge Frame These filters are equipped with a straight knurling edge for non-slip, easy attachment and removal. UV Protected Case Filter cases are UV protected to further lengthen the life of filters.