The tiffen 52mm ht neutral density 12 filter reduces the amount of light entering the lens by 4 stops without changing the colour of the scene because of the 4 stop decrease you are able to use the aperture you need to enable you to play with backgrounds distance and depth of field or to use long exposures slow shutter speeds to give an impression of motion they are often used in bright conditions when capturing landscapes and seascapes these tiffen ht filters with hi trans double sided