The 100x150mm GND4 (0.6) Nano IR Medium Graduated Neutral Density Filter from NiSi is a rectangular filter that helps to darken specific areas of an image, such as bright skies, while allowing for a normal, unaffected exposure in the other regions of the image. With a 0.6 density, it will provide a 2 stop reduction in light from entering the lens. The filter is densest at the edge and tapers to clear by the middle, with a medium-edged line of transition between the dense and clear areas. This makes it particularly useful for images that feature buildings, mountains and other elements that protrude into the skyline. Normally, when using a neutral density filter the camera is vulnerable to infrared light which can cause an unwanted red colour cast in images when shooting at small apertures. To prevent this, NiSi has added the infrared protection coating layer to this filter which helps to eliminate the infrared light through the lens to bring back the natural colour. Made from high quality optical glass, it preserves every bit of detail and will not affect the colour of your image. It also features NiSi’s unique nano coating technology which reduces reflection on the surface of the filter to help with ghosting and flare. In addition, a protective layer makes it easy to wipe off water, dust, and oil from the filter without worrying about scratching your glass. This filter measures 100 x 150mm and is compatible with the Nisi 100mm filter holder or other 100mm Standard Filter Holder (Lee, Cokin or Formatt Hitech). The filter can be repositioned in the holder, allowing you to recompose the photo for the best result.