The 0.9 100 x 150mm Hard-Edge Reverse Graduated Nano IRND Filter from NiSi is compatible with filter holders that support 2mm-thick, 100 x 150mm rectangular filters, including the NiSi 100mm system. It can be used to darken bright skies, specifically during a sunrise or sunset, while allowing for a normal, unaffected exposure in the other regions of the image.
This filter has a 0.9 band of density across its center region. After a hard-edged line of transition, it tapers to a clear area. This design allows the filter to match the sun's position when it is at or immediately above the horizon. The hard-edged line of transition is useful for hard transitions between the sky and land. The filter features a waterproof and low reflection nano coating and comes with a leatherette carry pouch.