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Encyclopedia > Filter (photography)

In photography, a filter is a camera accessory consisting of an optical filter that can be inserted in the optical path. The filter can be a square or rectangle shape mounted on a holder accessory, or, more commonly, a glass or plastic disk with a metal or plastic ring frame, which can be screwed in front of the lens. Photography is the process of making pictures by means of the action of light. ... A camera is a device used to take pictures (usually photographs), either singly or in sequence, with or without sound recording, such as with video cameras. ... Coloured and Neutral Density filters An optical filter is a device which selectively transmits light having certain properties (often, a particular range of wavelengths, that is, range of colours of light, or polarizations), while blocking the remainder. ... A lens. ...

55mm filters
55mm filters

Filters allow added control for the photographer of the images being produced. Sometimes they are used to make only subtle changes to images; other times the image would simply not be possible without them. Image File history File linksMetadata Download high resolution version (1035x280, 213 KB)Three 55mm camera filters. ... Image File history File linksMetadata Download high resolution version (1035x280, 213 KB)Three 55mm camera filters. ...


The negative aspects of using filters, though often negligible, include the possibility of loss of image definition if using dirty or scratched filters, and loss of some exposure. The former is best avoided by careful use and maintenance of filters, while the latter usually will not be a problem if planned out properly. A photograph with an exposure time of 25 seconds In photography, exposure is the total amount of light allowed to fall on the sensor (photographic film or CCD) during the process of taking a photograph. ...


Many filters are identified by their Wratten number. Wratten numbers are a labeling system for optical filters, usually for photographic use. ...

Contents


Types of filters

There are several types of filter in common use:

An infrared filter is a filter to remove visible light and only pass infrared light in different wavelenghts. ... In photography and optics, a neutral density filter or ND filter is a grey filter;. In theory, a neutral density filter reduces light of all wavelengths or colors equally, much like inexpensive sunglasses. ... A sunset at Zion National Park. ... Polaroid UV filter UV filters are used for general photography to reduce haziness or fogginess created by ultraviolet light. ... Special effects (abbreviated SPFX or SFX) are used in the film, television, and entertainment industry to create effects that cannot be achieved by normal means, such as depicting travel to other star systems. ... Schematic drawing of the effects of diffusion through a semipermeable membrane. ... Sepia tone is a type of monochrome photographic image in which the picture appears in shades of brown as opposed to greyscale as in a black-and-white image. ...

Clear

Clear filters, also known as window glass filters or optical flats are (ideally) completely transparent, and thus not (technically) really filters at all. They are generally used to protect the front of a lens. UV filters are also often used for this purpose. While in certain cases (such as harsh environments like deserts or mud wrestling rings) this is obviously necessary, there is a debate within the photographic community as to whether or not this is a sound practice. Polaroid UV filter UV filters are used for general photography to reduce haziness or fogginess created by ultraviolet light. ... Desert view in Saudi Arabia. ... Mud wrestling involves participants, usually women, wrestling in mud. ...


Naysayers claim:

  • adding another element degrades (however so slightly) image quality
  • if the lens is dropped, the "protective" filter may well shatter and scar the lens it is supposed to be protecting
  • it may provide a false sense of security, causing users to be less careful, or not use lens caps.
  • it may reduce the use of lens hoods, since threading a lens hood on top of the clear filter might cause vignetting on some lenses, and since not all clear filters would even have threads allowing a hood to be attached.
  • it is part of the culture of convenience, and detracts from the care with which the photographic process should be approached.

People in favor of the practice claim: A lens hood used on the Canon EF 70-200mm lens In photography, a lens hood is a device used with lenses to block the sun to prevent sun glare. ... An example of vignetting in a photograph. ...

  • if the lens is dropped, the filter may well suffer scratches or breakage instead of the front lens element.
  • one can clean the filter frequently without having to worry about damaging the lens coatings; a filter scratched by cleaning is much less expensive to replace than a lens.

Color correction

WANKERS


Color subtraction

Contrast enhancement

Monochrome

Filters are commonly used in black and white photography to manipulate contrast. For example a yellow filter will enhance the contrast between clouds and sky by darkening the latter. Orange and red filters will have a stronger effect. This article is about the term as used in media and computing; for more specific uses, see Black and White. ... Contrast has several meanings: // Visual perception Left side of the image has low contrast, the right has higher contrast. ...

Effects of using a polarizer and a red filter in black-and-white photography

Image File history File links El_Gouna_Egypt_BW_Filter_Comparison_EN.png The effect of using polarizer and red filter in black-and-white photography. ... Image File history File links El_Gouna_Egypt_BW_Filter_Comparison_EN.png The effect of using polarizer and red filter in black-and-white photography. ...

Polarizer

A polarizing filter, used both in color and black and white photography, can be used to darken overly light skys. Because the clouds are relatively unchanged, the contrast between the clouds and the sky is increased. Atmospheric haze and reflected sunlight are also reduced, and in color photographs overall color saturation is increased. A polarizer is a device that converts an unpolarized or mixed-polarization beam of electromagnetic waves (e. ... This article is about the term as used in media and computing; for more specific uses, see Black and White. ...

The effects of a circular polarizer on the sky in a color photograph.
The effects of a circular polarizer on the sky in a color photograph.
In the first picture, the polarizer is rotated to minimise the effect, and in the second it is rotated 90° to maximise the effect - almost all reflected sunlight is eliminated.
Enlarge
In the first picture, the polarizer is rotated to minimise the effect, and in the second it is rotated 90° to maximise the effect - almost all reflected sunlight is eliminated.

There are two types of polarizing filters. A linear polarizer filter creates linearly polarized light. A circular polarizer creates circularly polarized light, by adding a second birefringent layer to the filter after the linear polarizer. The metering and auto-focus sensors in certain cameras, notably SLRs, will not work properly with linear polarizers, both because of the mirror and because of the beam-splitters used to split off the light for focusing and metering. Circular polarizers will work with all types of cameras. ImageMetadata File history File links Download high resolution version (2484x946, 874 KB) The effects of a circular polarizer in a color photograph. ... ImageMetadata File history File links Download high resolution version (2484x946, 874 KB) The effects of a circular polarizer in a color photograph. ... Image File history File linksMetadata Download high resolution version (900x300, 45 KB) Summary Mudflats, showing effect of rotating polarising filter Licensing I, the creator of this work, hereby release it into the public domain. ... Image File history File linksMetadata Download high resolution version (900x300, 45 KB) Summary Mudflats, showing effect of rotating polarising filter Licensing I, the creator of this work, hereby release it into the public domain. ... In electrodynamics, polarization (also spelled polarisation) is a property of waves, such as light and other electromagnetic radiation. ... A calcite crystal laid upon a paper with some letters showing the double refraction Birefringence, or double refraction, is the decomposition of a ray of light into two rays (the ordinary ray and the extraordinary ray) when it passes through certain types of material, such as calcite crystals, depending on... The single-lens reflex (SLR) is a type of camera that uses a movable mirror placed between the lens and the film to project the image seen through the lens to a matte focusing screen. ...


Cross screen

Diffusion

A diffusion filter softens subjects and generates a dreamy haze. Photon diffusion referes to a situation where photons travel through a material with a high optical depth and very short mean free path. ... A diffusion filter is a photographic filter used for a special effect. ...


Materials and construction

Photo filters are commonly made from glass, resin plastics similar to those used for eyeglasses (such as CR39), polyester, or gelatin. Sometimes a color is blended throughout the filter material, in other cases the filter is a sandwich composed of a thin sheet of material surrounded and supported by two pieces of clear glass or plastic. This article refers to the material. ... Insect trapped in resin. ... CR-39, or allyl diglycol carbonate, is a plastic polymer commonly used in the manufacture of eyeglass lenses. ... For the film, see the article Polyester (film) Close-up of a polyester shirt SEM picture of a bend in a high surface area polyester fiber with a seven-lobed cross section Polyester is a category of polymers, or, more specifically condensation polymers, which contain the ester functional group in... Gelatin (also gelatine) is a translucent brittle solid substance, colorless or slightly yellow, nearly tasteless and odorless, which is created by prolonged boiling of animal skin, connective tissue or bones. ...


Certain kinds of filters use other materials inside a glass sandwich; for example, polarizers often use various special films, netting filters (a kind of contrast filter) have nylon netting, and so forth.


The rings on screw-on filters are most often made of aluminum, though in more expensive filters brass is used. Aluminum filter rings are much lighter in weight, but can "bind" to the aluminum lens threads they are screwed in to, requiring the use of a filter wrench to get the filter off of the lens. Aluminum also dents or deforms more easily.


Filter sizes and mountings

Manufacturers of lenses and filters have "standardized" on several different sets of sizes over the years.


Threaded round filters

For circular filters, standard sizes include 49 mm, 52 mm, 55 mm, 58 mm, 62 mm, 67 mm, 72 mm, 77 mm, and 82 mm; within this range, other sizes may be hard to find. The thread pitch is 0.5 mm or 0.75 mm, depending on the ring size. Three different sets of threading gauges Threading gauges, pictured on the right, are also referred to as pitch gauges and are used to measure the pitch or lead of the screw threads. ...


Square filters

For square filters, 2" x 2", 3" x 3" and 4" x 4" were historically very common and are still made by some manufacturers. 100mm x 100mm is very close to 4"x4", allowing use of many of the same holders, and is one of the more popular sizes currently (2006) in use; it is virtually a standard in the motion picture industry. 75mm x 75mm is very close to 3" x 3" and while less common today, was much in vogue in the 1990s. For other uses see film (disambiguation) Film refers to the celluliod media on which movies are printed Film — also called movies, the cinema, the silver screen, moving pictures, photoplays, picture shows, flicks, or motion pictures, — is a field that encompasses motion pictures as an art form or as part of...


A French manufacturer called Cokin makes a wide range of filters and holders in three sizes. "A" (amateur) size is 67 mm wide, "P" (professional) size is 84 mm wide, and "X Pro" is 130 mm wide. Many other manufacturers make filters to fit cokin holders. Cokin also makes a filter holder for 100 mm filters, which they call the "Z" size. Cokin is a French manufacturer of optical filters for photography, including nonstandard-shaped filters such as rectangular graduated neutral density filters. ...


Rectangular filters

Graduated filters of a given width (100 mm, 67 mm, 84 mm, etc.) are often made rectangular, rather than square, in order to allow the position of the gradation to be moved up or down in the picture. This allows, for example, the red part of a sunset filter to be placed at the horizon.


Bayonet round filters

Certain manufacturers, most notably Rollei and Hasselblad, have created their own systems of bayonet attachment for filters. Each design comes in several sizes, such as Bay I through Bay VI for Rollei, and Bay 60 through Bay 93 for Hasselblad. Rolleiflex medium format camera Rollei is a German manufacturer of optical goods, and maker of the well-known Rolleiflex and Rolleicord series of cameras. ... Hasselblad 503CW with Zeiss Distagon 3,5/30 and Ixpress V96C Hasselblad is a Swedish manufacturer of high-quality still photography cameras based in Gothenburg, Sweden. ...


Series filters

From the 1930s through the late 1970s, filters were also made in a sizing system knows as a series mount. The filters themselves were round pieces of glass (or occasionally other materials) with no threads or rings attached. Instead, the filter was placed between two rings; the mount ring screwed into the lens, the retaining ring held the filter against the first ring. The series designations are generally written as Roman numerals, I through IX, with the interesting exception of the series 4.5 filter. The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ...


Stuck filter removal

A stuck filter with an aluminum ring should not be removed by squeezing from both sides with your hand; aluminum deforms and this could permanently warp the filter, damaging it and also making removal even more difficult. If the filter is stuck and a filter wrench is not available, cup the whole filter with a piece of fabric and press it down against something solid. Then twist the lens barrel to unstick things.


See also

Coloured and Neutral Density filters An optical filter is a device which selectively transmits light having certain properties (often, a particular range of wavelengths, that is, range of colours of light, or polarizations), while blocking the remainder. ... // List of camera manufacturers Alpa ARCA Swiss Cambo Canham Canon Contax Cosina Ebony (camera maker) Fotoman Fujifilm Gandolfi Gowland Graflex Hasselblad Holga Horseman Kiev-Arsenal (photo camera) Kodak Konica Minolta Kyocera Leica Leningradskoye Optiko Mechanichesckoye Obyedinenie(LOMO) Linhof Littman Mamiya Minox Nikon Olympus Panasonic Pentacon (Praktica) Pentax Polaroid Ricoh Rollei...

External links

  • Photography Filters

  Results from FactBites:
 
Photography - MSN Encarta (1329 words)
Filters added to the front of a camera lens change the quantity or quality of the light that reaches the film.
In a landscape photograph taken with a red filter, for example, much of the blue light of the sky is blocked, causing the sky to appear darker and thereby emphasizing clouds.
The medium-yellow filter is often used for outdoor fl-and-white photography because it renders the tone of a blue sky in much the same way as the human eye does.
Steve's Desktop Photography - Plug-Ins - FF Galleries & Collections (1052 words)
These filters are compiled using the Plugin Commander into small FFL files.
Filter Factory Converter from Jan Angermueller is a freeware program to convert FF made Photoshop filters to the Adobe Premier format type filters.
If a Filter is declared as Freeware you can distribute it as you like, although the FF-Code is still owned by the author.
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