Filters in the digital age: the Polariser
By Shelton Muller
One of the most oft-employed filters is the polariser. When light is reflected from a surface it travels in a single plane, unlike normal daylight which vibrates in all directions. Polarising filters cut through this kind of light and thus remove unwanted reflections. At first thought, it may be felt that its usefulness is somewhat limited.
The Cokin 173 Blue Yellow Polariser is no ordinary filter
However, to the landscape or travel photographer its benefits can not be emphasised enough. Polarising filters can be used to remove highlights reflected from certain surfaces such as foliage and even the ocean.
The reflections from these surfaces weaken the colours and so a polariser removes the glare and intensifies the hues. As these reflections are removed, the colours appear as they would otherwise be seen.
Oceans become blue green and inviting, and landscapes become more colourful and the details are sharpened. Sky is partly polarised and a polariser will often deepen the blue.
This is most effective at right angles to the sun where the light is most polarised. Polarising filters are most successful when the lens axis is about 60 degrees to the reflecting surface.
But don’t try them on chrome or other shiny metals as they will have no effect whatsoever. Cokin make a polariser which has become very popular in the United States. The Cokin 173 Blue Yellow Polariser (as it is known) actually overcomes the “cold blue” tendency inherent in some polarisers. As landscape photographers prefer warmer tones in their images, this can be a disadvantage indeed.
The 173 Polariser (or “warming polariser” as it is affectionately known) overcomes this by restoring warm tones in the photograph. It accomplishes this while simultaneously deepening the blue in sky and ocean, making some knock out colours in these scenes.
But a word of caution: The Cokin 173 Polariser is in reality an “effect” filter and its effect can be overdone. As with all filters – use with discretion! For further information, Shelton Muller can be contacted at shelton@total-image.com.au
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