The Benro Magnetic Soft Grad Neutral Density 0.9 Filter helps to darken specific areas of an image, such as bright skies, while allowing for a normal, unaffected exposure in the other regions of the image. A neutral density filter with a soft-edged line of transition is particularly useful for images that do not have a strongly defined transition between the sky and the foreground. Neutral density filters do not affect the coloration of the image, and this filter provides up to a 3-stop reduction in light from entering the lens. Please note : This magnetic filter cannot be used alone. It needs to be used with a 82mm Magnetic Fixed Ring / Magnetic Step Down Ring to attach the magnetic filters onto the lens. If your lens is a different size thread, you may purchase 82-67mm / 82-77mm Magnetic Step Down Rings to suit other sizes of lens.