Description
The Hoya Variable Density filter uses two polarizing layers to control the amount of light that passes through the filter and into the camera lens. At its minimum effect the filter passes 1/3 of the light in a scene. That is equal to 1.5 stops on the aperture or shutter speed. At its maximum effect the filter passes just 1/400 of the light in a scene. That is equal to 9 stops on the aperture or shutter speed.