Photographic filter

Filter elements are of an optical system to be fitted in the photograph in front of the lens of the camera usually to modify the image before it impinges on the lens and the image sensor or film. This is accomplished by the nature and material of the filter.

Application

Filters are used in photography both as a correction as well as so-called filter effect. Can be changed saturation, contrast, UV light, or it can also elements and effects are added like stars.

Most filters reflect a portion of the incident light so that less light reaches the objective lens. This exposure is given by reducing the filter factor. This is usually indicated on the version of the filter.

Important filters are:

• ( Also called short Polarizer ) polarization filter
• UV blocking filter (usually referred to as a UV filter ) and Skylight
• Color filter or conversion filter and correction filters (red, green, blue, yellow etc. )
• Special optical filter
• Infrared blocking filter
• Neutral density filter ( ND filter short, usually also referred to as a neutral density filter )
• Effect Filters

With digital photography, many filters are hardly used because the effects can be applied in many cases, subsequently, with the help of image processing and an image editing program in photographs (especially the effect and color filter; see graphic filter). However, UV, ND and polarizing filters are still irreplaceable. Furthermore, digital cameras almost always have a built- infrared cut filter between the lens and image sensor.

Correction filter

Common correction filter in black and white photography are yellow, orange, and red filters. They reduce the amount of blue and do with it especially shots with Blau-/Weißanteil ( sky) contrast.

For color photography are a whole series of colored filters. These are red-brownish and the various blue filter to use an artificial light film in daylight or a daylight film in artificial light.

A common filter in both color and black and white photography is the skylight. It prevents a blue cast.

Remove polarizing filter ( or strengthen, depending on the setting of the polarizing filter ) the reflections on non -metallic surfaces. In addition, the colors appear more intense.

Effect Filters

There are countless effects filters; the most commonly used include Soft Focus and filters that radiation wreaths can be created around lights. There are also various color filters, gradient filters and other filter trick.

Filter Adapter

Filter adapters are needed to connect the filter with a lens of a camera can. Distinction can be made for the filter between screw and plug filters. Accordingly, there are also different adapters for this purpose.

Spin

Due to the various filter thread, there are filter adapter to connect filter to lenses with different filter thread diameters can. Thus, the filter produces no additional vignetting, it is only sensible to close larger filters to smaller thread.

The designation 52 → 55 indicates that a 55 -er to a 52 it can be adapted lens filter.

Plug-in filters

With plug-in filters can hold various accessories such as filters, lens hoods or lens cap to be attached to different sized filter threads. A filter may be used on a wide variety of lenses. For this you need a filter holder and an adapter ring with the filter diameter of each lens. So not the perfect accessory must be purchased for each lens. Plug-in filter systems of different sizes are produced, inter alia, by Formatt Hitech, Cokin and Lee.

High-quality plug-in filters, which are made of the CR -39 polymer will have an optical quality that is comparable of crown glass and thus the classic screw- not inferior glass.

Graphics filters

In digital image processing, the effect of many optical filters can be generated by so-called graphics filters.