This B+W gray filter, which reduces exposure by six f-stops, is considered an extreme filter in photographic imaging. It allows for an exposure time of one second from 1/60 s without changing the aperture (and depth of field). Flowing water is rendered delicately and ethereally. A tripod is required in any case.

The thin-film technology developed here not only provides the pure ND filter effect but also optimizes the ND filter with a combination of coatings. In addition to the filter effect, the coating combination includes a multi-layer anti-reflective component with seven layers per filter side to prevent disturbing reflections. As a finishing touch, an outer layer with well-known dirt and water-repellent properties is applied. This not only protects the filter all around but also allows for easy cleaning and maintenance of the filter glass. The light attenuation itself is very uniform across the entire visible spectrum, resulting in optimally color-neutral image results.