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What is a Polarizer Filter ?

Updated on May 7, 2013

Filters are a good option because they produce effect that may be difficult to produce during post-processing and others have effects which cannot even be re-produced.

Polarizing – linear/circular – They reduce the amount of light that passes through to your camera sensor changing the exposure of the image. This means you therefore need to use longer exposures to accommodate more light i.e. the shutter speed, aperture or the ISO. The polarizer only have an effect on very bright sunlight and this makes it hard to use it during the night or when you have inadequate lighting like indoors or when it’s cloudy. Also ensure that your camera is steady to avoid the blur caused by the camera shake due to longer exposures.

Mostly used in scenes with high reflections and glare e.g. water, sky, road etc. The intensity of polarization can be changed by rotating the polarizing filter and monitoring the effect through the viewfinder until you get the desired effect. The strength of the effect varies depending on the angle of the sun. Use the polarizer when the sun is above at 90^o as this will have the greatest effect on your image.

Sky – changes from light pale to deep blue sky.

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Reduce reflection off water – reduces the reflection, improves the colour saturation

Reduce contrast between land and sky – reduces light to darken the sky and the land below it, emphasizing on the clouds since they are affected just a little bit. It also cuts the haze that result under very bright sunlight especially when shooting mountain ranges.

Glass windows – reduces the light reflected making subjects to be seen through.

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Vegetation under bright sun – improves the colour saturation by reducing the light reflected by the leaves bringing out the natural colour. Vegetation looks greener and brings out powerful tones and colour that are not visible under too much light.