Reduces/modifies intensity of wavelengths equally
Renders no change in color hue
Allows greater flexibility with camera settings
In photography and optics, a neutral density filter reduces and/or modifies intensity of all wavelengths or colors of light equally, giving no changes in hue of color rendition. The purpose of a standard neutral density filter is to allow the photographer greater flexibility to change the aperture, exposure time, and/or motion blur of subjects in different conditions.