 Polarizing filters also help with cutting glare from water reducing reflections, snow and ice—even facilitating greater transparency of water and ice.Neutral density filters are darkened with a neutral (colorless) gray tint which reduces the amount of light entering the camera lens.These filters are used to lengthen shutter speeds without the need to alter aperture or film/sensor sensitivity, or alternatively, to use large apertures without exceeding the maximum shutter speed of a camera.