Cokin is a French manufacturer of

optical filter An optical filter is a device that selectively transmits light of different wavelengths, usually implemented as a glass plane or plastic device in the optical path, which are either dyed in the bulk or have interference coatings. The optical ...

s for

photography Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employe ...

. The system allows filters such as rectangular

graduated neutral density filter 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 whi ...

s which are versatile in use.

History

Cokin are particularly noted for their "Creative Filter System". It was invented by photographer Jean Coquin and introduced in 1978. Based primarily around square filters, these require a holder which is attached to the lens via a simple adapter ring of the appropriate size. Unlike screw-thread circular filters, which are each tied to lenses of a specific diameter, those in the system can be used with any lens, provided they are large enough to cover it sufficiently. (Only the adapter ring may need changing).

Production

The system includes a wide range of filters including

color correction Color correction is a process used in stage lighting, photography, television, cinematography, and other disciplines, which uses color gels, or filters, to alter the overall color of the light. Typically the light color is measured on a scale kno ...

, plain and coloured graduated filters, diffraction,

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemica ...

and polarizers. The material is a polymer,

CR-39 Poly(allyl diglycol carbonate) (PADC) is a plastic commonly used in the manufacture of eyeglass lenses alongside the material PMMA (polymethyl methacrylate). The monomer is allyl diglycol carbonate (ADC). The term CR-39 technically refers to the ...

sometimes advertised as "organic glass". Cokin produce various differently-sized versions of the Creative Filter System. The smallest is "A" ("Amateur", 67mm wide). The larger "P" ("Professional", 84mm wide) system covers cases where "A" filters are too small to cover the lens (or would cause problems at wider angles). The still-larger "X-Pro" filters are 130mm wide. The "A" and "P" sizes in particular are

de facto ''De facto'' ( ; , "in fact") describes practices that exist in reality, whether or not they are officially recognized by laws or other formal norms. It is commonly used to refer to what happens in practice, in contrast with ''de jure'' ("by la ...

standards, with many other manufacturers producing compatible filters and holders. Cokin also produce a system for 100mm-wide filters which they refer to as "Z-Pro". "X-Pro" and "Z-Pro" are designed for larger cameras.

References

External links

Cokin UK website
Optical filters {{France-company-stub