Neutral Density filters (ND filters) are used in photography to reduce the overall amount of light entering the camera. ND filters don’t affect the hue or colour rendition as the intensity of all wavelengths of light is affected equally. Neutral density filters allow photographers to longer shutter speeds.
Particularly popular with landscape photographers, ND filters let photographers create photos that otherwise wouldn’t be possible, by using a smaller aperture and a longer shutter speed for images with a narrow depth of field and motion blur – for example running water or light trails.
Neutral density filters are available in a variety of stop-levels and densities from leading brand manufacturers such as Hoya, LEE filters, Hama, and Tiffen.