the marumi dhg grey variable filter is of the same quality as a professional ‘top filter’ for a fraction of the price. the dhg series filters are made up of a special coating to counteract unwanted reflections, a matte black metal rim and black glass edges to minimize internal reflections. the marumi dhg grey variable filter is a nd filter composed of 2 polarizing filters, which is screwed onto your camera lens. differing from the standard nd2, nd4 and nd8 filters, the grey variable filter has an outer ring, which can be rotated to adjust the density of the filter to suit the lighting conditions and effect you wish to achieve. due to this, a single grey variable nd filter can replace an entire series of standard grey nd filters, making it both, cost and time, efficient. the aperture can be delayed from 2 to 8 stops. marumi dhg grey variable filter possibilities a grey filter can help you achieve the following effects: blurred motion photography in regards to water such as waterfalls, rovers and oceans (see photo 3) reduction of the depth of field in bright light situations applying a high aperture with affecting the diffraction/resolution of your images