A marumi dhg super nd (digital high grade natural density) is a grey filter that gives you the possibility to control the incoming bright light in the lens. Because of the multi coating in these super nd500 filters the reflection of the incoming light is very reduced without disturbing the color balance. When there is too much light or for example you want to, use a different aperture with the same shutter speed you can use a gray filter. The light intensity is reduced by this filter. With this marumi dhg super nd500 filter you can lower a certain aperture value with 9-stops. So a slower shutter speed with constant aperture. You do not have to squeeze the aperture if you want a slower shutter speed. Because of this slower shutter speed you are able to capture movement in a photo and you prevent the moving image from being duplicated '' ghosting ''. A good example is a photograph of running water as shown in the pictures. Features dhg filters the dhg filters are made of extra strong tempered glass and have a multi coating, making them water, scratch and dirt resistant. The dhg filters are also easy to clean. The female thread allows the stacking of filters so you can combine different filters for even more effects. Prevents ghosting and reflection optimal light transmission through multi coating with the right diameter suitable for every camera lens metal housing without vignetting (no darkening in the corners) also suitable for wide-angle lenses and full-frame cameras black coating on the outer edge of the lens for minimal reflection