The 3-stop, 150 x 170mm Nano Hard-Edge Graduated IRND Filter from NiSi has a rectangular shape and helps darken specific areas of an image, such as bright skies, while allowing for normal, unaffected exposure in other parts of the image. The filter is densest at the edge and tapers to clear by the middle, with a hard-edged line of transition between the dense and clear areas. A neutral density filter with a hard-edged line of transition is particularly useful for images that feature a prominent horizon, or any hard transition between the sky and land. Neutral density filters do not affect the coloration of the image and this filter provides up to a 3-stop reduction in light from entering the lens.
Constructed from optical glass for clarity as well as color fidelity, this filter has been optimized for use with digital sensors and to promote nearly flat attenuation of visible and infrared light. To provide a high level of neutrality across the visible and infrared spectrums to eliminate color casts and ensure cleaner, truer blacks, NiSi Optical Nano Coating is applied to each of this filter's surfaces. The Nano coating associated with this filter also results in an improved beading effect when in contact with water or oil for greater cleaning efficiency. This filter is 2mm thick and fits most filter holder systems that are 150mm wide.