Filters can help produce better photos. However, the quality differences between filters are huge. If you have an expensive lens, you do not want to run the risk of image quality losses due to inferior filters. Rodenstock guarantees the best possible filter quality. Optical glass for filters must meet very stringent demands. The glass must be homogeneous, and both surfaces must be “plan parallel”. The surfaces must be smooth. The polish must be equal to that of the surfaces of camera lens elements. The filter frame may not project too far beyond the front edge of the lens barrel so that the filter does not cause vignetting with wide-angle shots. All Rodenstock filters have a very flat slim line frame. In order to allow a front thread, the Rodenstock glass is only 1.4mm thick, compared to other filters are 2.0mm thick or thicker. The frames of the Rodenstock Digital Pro filters are made of aluminum because these filters were designed for the best possible price/performance ratio. The edges of all Rodenstock filter Lenses are blackened so that no contrast-reducing reflections are caused there. If you need more than the ND 2x, 4x and 8x, or want finer graduations, the variable neutral density filter Rodenstock Digital Pro Vario ND. It consists of two polarization filters continuously adjustable from 1.5 to 5 stops. Color neutrality is gradually lost above 5 f-stops. Furthermore, with very wide-angle lenses, disturbing cruciform shading occurs close to the maximum position. Because these very high settings cannot be recommended, the setting scale of the Rodenstock Digital Vario ND only indicates the sensible attenuation range 1.5 to 5: without cruciform shading and without a blue-violet color tinge. Digital Pro Vario ND filters with Multi-coatings have: The best optical glass The perfect optical surface quality A multi-coated scratch resistant surface A rugged slim aluminum ring with front thread Are compatible with most wide-angle lenses