Graduated ND filters are part clear, part neutral density (available in grades of .3 (1 stop), .45 (1.5 stops), .6 (2 stops), .75 (2.5 stops), .9 (3 stops). They allow the reduction of light to part of a scene, balancing light and dark for an even exposure. Lee graduated neutral density filters are available with soft, hard or blended transitions from dark to clear. The soft edge is recommended for wide angle lenses and the hard edge is recommended for normal and longer lenses