The NiSi 75x100mm Nano IR Medium Graduated Neutral Density Filter – ND4 (0.6) – 2 Stop 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. 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. A neutral density filter with a medium-edged line of transition is particularly useful for images that feature buildings, small mountains and other elements that protrude into high into the skyline. The transition zone of a medium is 40% smaller than a Soft GND and is wonderful for shooting at sunrise and sunset. NiSi GND filters do not affect the colouration of the image, offer a true to life colour and are made from high-quality optical glass (not resin) with nano coating to prevent losing any single bit of detail. By using neutral density filter the camera is vulnerable to infrared light which will cast the unwanted red colour to the photos when shooting at a small aperture. NiSi GND filters have an infrared protection coating layer to eliminate the infrared light through the lens to bring back the natural true to life colour. The NiSi M75 filter system is great for compact and mirrorless cameras with lenses that have a standard filter thread from 40.5mm to 67mm. This 75x100mm filter is compatible with the NiSi M75 filter system.