 A variation of this filter, termed the graduated neutral density filter or simply 'ND grad', transitions from dark, neutral gray on one side to clear on the opposite side.Photographers use these filters to lower natural contrasts by reducing light transmission from the brightest portion of the subject landscape, while letting light from the darker portion of the landscape enter the lens unobstructed.UV-Zero haze filters reduce "purple fringing" caused by ultraviolet light, especially in digital situations.