Neutral Density filters evenly reduce the amount of light passing thru the lens without effecting color. Ideal for reducing bright light in large aperture situations when a narrow depth is field is needed. Allows for slower shutter speeds when blurring or showing of movement is desired. Allows balancing of exposure to highlight a key subject. Lets you use higher speed films in bright light.0.3 (2X) Reduces the light one f-stop.Size: 60mm.