A graduated neutral density filter, also known as a graduated ND filter, split neutral density filter, or just a graduated filter, is an optical filter that has a variable light transmission. Typically half of the filter is of neutral density which transitions, either abruptly or gradually, into the other half which is clear. It is used to bring an overly-bright part of a scene into the dynamic range of film or sensor. For example, it can be used to darken a bright sky so that both the sky and subject can be properly exposed. ND filters can come in a variety of shapes and sizes and densities and can be used in all types of photographic applications from still photography, motion photography and scientific applications.
Center-spot filters are ND graduated filters that are slightly opaque in the center and are clear at edges. These are used for special effects or to compensate for light falloff that is natural with large optics.
Read more about Graduated Neutral Density Filter: History, Types
Famous quotes containing the words graduated and/or neutral:
“If you had made the acquiring of ignorance the study of your life, you could not have graduated with higher honor than you could to-day.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“The United States must be neutral in fact as well as in name.... We must be impartial in thought as well as in action ... a nation that neither sits in judgment upon others nor is disturbed in her own counsels and which keeps herself fit and free to do what is honest and disinterested and truly serviceable for the peace of the world.”
—Woodrow Wilson (1856–1924)