The tiffen 67mm ht graduated neutral density 06 filter is a graduated filter designed to balance light intensity between two areas within a scene such as landscapes eg it allows you to grab more detail from the sky while properly exposing the foreground this is possible thanks to the unique design of the filter the nd grads are clear at the bottom half with a gradual transition of the nd effect in the top half of the filter designed for the discerning professional and imaging enthusiast th