This B+W Nd filter, which reduces the light by two f-stops, already shows a clear effect on your photographs such as requiring f/4 instead of f/8 for selective focus or 1/15 sec instead of 1/60 sec for a long exposure effect. The filter is color-neutral, and it should be part of any basic Dslr photography equipment kit.The excellent finely ground and polished special glass is used as the basis for the new Nd filter glasses. This guarantees the necessary optical quality and also does not have any adverse effect on a correspondingly high-quality lens.With the thin-film technology developed here, not only the pure Nd filter effect comes into play, but a coating combination optimizes the Nd filter. In addition to the filter effect, the coating combination contains a multi-layer anti-reflective component with 7 layers per filter side to prevent annoying reflections. An outer layer with the usual dirt- and water-repellent properties is applied as the final layer. This not only provides all-around protection for the filter, but also makes it easy to clean and maintain the filter pane. The light attenuation itself is very uniform over the entire visible range and produces optimally color-neutral image results.Note: Nd filters must not be used for direct visual solar observation (risk of blinding). They let through Uv- and Ir-rays which harm the eyes. Special sun filters for direct observation of the sun are available from astronomy suppliers..