For both still photography and video use the hoya 55mm variable density x3 400 filter makes it easy to adjust the brightness of a scene as well as gives more control over the exposure settings of your camera by rotating the inner filter ring the filter decreases light transmittance between approximately 13 and 1400th of its original level this permits aperture values to be set dependant on the desired effect and allows a much greater range of shutter speed for example in full s