The 150x170mm Nano IR Hard Graduated Neutral Density filter from NiSi is specially designed for landscape photographers. This filter is made from high quality optical glass (not rasin) with nano coating to prevent losing any single bit of detail. Neutral density filters do not affect the coloration of the image and the 0.9 density provides a 3 stop reduction in light from entering the lens. This filter measures 150 x 170mm and is compatible with the NiSi 150mm filter holders. The filter can be repositioned in the holder allowing recompose the photo for the best result.
Hard grad filters are commonly used to control the exposure on even horizons and when the horizon is level or unbroken such as coast lines.
By using neutral density filter the camera is vulnerable to infrared light which will cast the unwanted red color to the photos when shooting at small aperture. NiSi added the infrared protection coating layer to this filter which help to eliminate the infrared light through the lens to bring back the nature color.