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.
A GND filter held up to the horizon. Note the poor contrast in the overexposed part of the sky not covered by the filter.The same image with washed-out (white) pixels colored red. Note that clouds that are washed out without the GND filter show detail behind the filter.
Center-spot filters are ND graduated filters that are slightly opaque in the center and are clear at edges.[1] These are used for special effects or to compensate for light falloff that is natural with large optics.
The same image with a GND-like effect applied to the right side of the image using a computer. While the overall effect is similar, regions of the image that were washed out are not recovered.
Graduated filters were used in the early twentieth century, for example for darkening skies in landscape photos.[2] One advertised brand was called the "Lifa graduated filters for sky, cloud, and landscape photography".[3] These "sky filters" were not necessarily neutral, since they were used for black-and-white photography, and sometimes used a yellow top half to darken blue skies more.[4] In a discussion at the Royal Photographic Society in 1910, some "debatants" held the use of such "graduated color screens" to be quite limited.[5]
In more modern times, the use of graduated ND filters was popularized by Galen Rowell. Singh-Ray sold them as "The Singh-Ray set of 4 Galen Rowell Graduated Neutral-Density Filters."[6]
Although its importance may have lessened with the advent of the modern digital darkroom, graduated ND filters are still an important tool for professionals because a digital sensor that is clipping ("blown out" or "washed out") captures no usable data in the clipped area, an effect which cannot be corrected with later processing because data has been lost.
Typesedit
A Cokin 3-stop (ND8) graduated ND filter.Stacked cases of Cokin filters.
The filter comes in many types but can be separated into two basic categories:[7]
Hard edge
Soft edge
A hard edge is used when there is an abrupt change in brightness, such as a field with a horizon to a bright sky. A soft edge is a wider, smoother change from light to dark. This is used when the light and dark portions are not distinctly separated, such as a mountain and sky. A soft edge filter is less noticeable than a hard edge. It also has the benefit of making the sky more intense, darkening the sky the closer on the top. Below is a picture of what a hard edge and soft edge filter would look like.
Soft-edge GND filter
Hard-edge GND filter
Multi-shoots high dynamic rangeedit
As an alternative to split graduated neutral density filters, some digital cameras offer built-in high-dynamic-range imaging (HDR) which allow the camera to capture and then combine different exposures of the same subject matter when shooting in RAW image format.
However, as long as a sufficiently short exposure time is available, it is possible to exactly mimic the effect of a graduated neutral density filter by using two exposures of the same scene one or several stops apart and blending them with a graduated mask in an image editor. This method has the advantage that the shape of the mask can be freely defined in editing. The disadvantage is that it only works with static subjects using a tripod.
Referencesedit
^"These New Filters Create Amazing Photos". Popular Mechanics. 155 (4). Hearst Magazines: 116–117. April 1981.
^L. R. Gwyer (1908). "The Prismatic Filter". The Photographic Times. 40. Photographic Times Publishing Assn.: 113.
^Edward John Wall (1922). Practical Color Photography. Vol. 14. American Photographic Publishing Co.
^"Changing Bait". American Photographer. American Photographic Pub. Co.: 358 1920.
^"British Photographic Notes". The Professional and Amateur Photographer: 264. May 25, 1910.
^Katrin Eismann; Sean Duggan; Tim Grey (2003). Real World Digital Photography. Peachpit Press. ISBN978-0-321-22372-2.
^Bryan F. Peterson (2004). Understanding Exposure: How to Shoot Great Photographs with a Film Or Digital Camera. Amphoto Books. p. 150. ISBN978-0-8174-6300-7. hard soft edge graduated neutral density filter.
External linksedit
An effective demonstration picture
Image Tools Filter - Brightness
Wikimedia Commons has media related to Graduated neutral density filter.
January 01, 1970
graduated, neutral, density, filter, graduated, neutral, density, filter, also, known, graduated, filter, split, neutral, density, filter, just, graduated, filter, optical, filter, that, variable, light, transmission, typically, half, filter, neutral, density,. 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 A GND filter held up to the horizon Note the poor contrast in the overexposed part of the sky not covered by the filter The same image with washed out white pixels colored red Note that clouds that are washed out without the GND filter show detail behind the filter Center spot filters are ND graduated filters that are slightly opaque in the center and are clear at edges 1 These are used for special effects or to compensate for light falloff that is natural with large optics Contents 1 History 2 Types 3 Multi shoots high dynamic range 4 References 5 External linksHistory edit nbsp The same image with a GND like effect applied to the right side of the image using a computer While the overall effect is similar regions of the image that were washed out are not recovered Graduated filters were used in the early twentieth century for example for darkening skies in landscape photos 2 One advertised brand was called the Lifa graduated filters for sky cloud and landscape photography 3 These sky filters were not necessarily neutral since they were used for black and white photography and sometimes used a yellow top half to darken blue skies more 4 In a discussion at the Royal Photographic Society in 1910 some debatants held the use of such graduated color screens to be quite limited 5 In more modern times the use of graduated ND filters was popularized by Galen Rowell Singh Ray sold them as The Singh Ray set of 4 Galen Rowell Graduated Neutral Density Filters 6 Although its importance may have lessened with the advent of the modern digital darkroom graduated ND filters are still an important tool for professionals because a digital sensor that is clipping blown out or washed out captures no usable data in the clipped area an effect which cannot be corrected with later processing because data has been lost Types edit nbsp A Cokin 3 stop ND8 graduated ND filter nbsp Stacked cases of Cokin filters The filter comes in many types but can be separated into two basic categories 7 Hard edge Soft edge A hard edge is used when there is an abrupt change in brightness such as a field with a horizon to a bright sky A soft edge is a wider smoother change from light to dark This is used when the light and dark portions are not distinctly separated such as a mountain and sky A soft edge filter is less noticeable than a hard edge It also has the benefit of making the sky more intense darkening the sky the closer on the top Below is a picture of what a hard edge and soft edge filter would look like nbsp Soft edge GND filter nbsp Hard edge GND filterMulti shoots high dynamic range editAs an alternative to split graduated neutral density filters some digital cameras offer built in high dynamic range imaging HDR which allow the camera to capture and then combine different exposures of the same subject matter when shooting in RAW image format However as long as a sufficiently short exposure time is available it is possible to exactly mimic the effect of a graduated neutral density filter by using two exposures of the same scene one or several stops apart and blending them with a graduated mask in an image editor This method has the advantage that the shape of the mask can be freely defined in editing The disadvantage is that it only works with static subjects using a tripod References edit These New Filters Create Amazing Photos Popular Mechanics 155 4 Hearst Magazines 116 117 April 1981 L R Gwyer 1908 The Prismatic Filter The Photographic Times 40 Photographic Times Publishing Assn 113 Edward John Wall 1922 Practical Color Photography Vol 14 American Photographic Publishing Co Changing Bait American Photographer American Photographic Pub Co 358 1920 British Photographic Notes The Professional and Amateur Photographer 264 May 25 1910 Katrin Eismann Sean Duggan Tim Grey 2003 Real World Digital Photography Peachpit Press ISBN 978 0 321 22372 2 Bryan F Peterson 2004 Understanding Exposure How to Shoot Great Photographs with a Film Or Digital Camera Amphoto Books p 150 ISBN 978 0 8174 6300 7 hard soft edge graduated neutral density filter External links editAn effective demonstration picture Image Tools Filter Brightness nbsp Wikimedia Commons has media related to Graduated neutral density filter Retrieved from https en wikipedia org w index php title Graduated neutral density filter amp oldid 1172336212, wikipedia, wiki, book, books, library,
