Filters in the Digital Age Part II
Filters for Landscape Photography

Shelton Muller looks at some Cokin filters no photographer – film or digital – should be without when venturing into the wide open spaces.

Polarisers

One of the most oft-employed filters is the polariser. The irreplaceable effect and benefit this filter brings cannot be replicated in the computer and as such every photographer should have one.

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. However, to the landscape or travel photographer its benefits cannot be stressed 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 colour and so a polariser removes the glare and intensifies the hues. As these reflections are removed, the colours appear as they would be seen without the disadvantage of polarised light. 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 produce a fabulous circular polarizer for this purpose. However, they have another polariser that 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, producing some knockout 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.

Graduating Filters

Graduating filters are those which have a colour or tone which graduates gently about halfway through the filter and deepen as they reach the top. Graduated filters come in all sorts of colours and can be used to enhance sunsets and colour otherwise bland and empty skies. The most useful graduated filter however is a graduated grey or neutral density filter as it can be used to maintain detail in overexposed areas – without making any distinct colour change. By so doing, the photographer can expose for foreground (which may require one or two stops more light) and still maintain detail in the sky or distant hills.

Without graduating filter (above left) and with (above right) – exposed for the boats. Getting it right in-camera with a grad filter saves a lot of post-processing work on scenes with shaded foreground subjects or white cloudy skies.

These kinds of filters are rarely found in screw-in mount types. While there are half-half type filters available, there is no graduation in the colour and a harsher line is visible. The advantage with slot-type filter systems is that the filter can be moved up and down in the adaptor to accommodate the photograph and its composition. Your best bet here is Cokin.

Again, this filter is irreplaceable in its value, especially if it is your desire to create images in-camera. Unlike the human eye, your digital sensor cannot record detail in both heavy shadows and bright highlights simultaneously. The Cokin enables the landscape photographer particularly to overcome this issue with the simple insertion of a Graduated Grey, Gradudated Blue, Graduated Tobacco or Sunset filter.

Shelton Muller is a Melbourne-based photographer and the editor of Total Image and Better Pictures magazines. He can be contacted via his website at www.photographybyshelton.com