UNDERSTANDING POLARISING FILTERS

The most versatile filter you could ever have in your kit bag

As soon as you begin taking landscape photography more seriously, the first filter you need to get is a polariser. For most photographers, this will be a screw-in type that fits the filter thread of the main lens you use for shooting landscapes. As you improve and demand more from your photography, you’ll probably upgrade to a drop-in filter system, and a dedicated polariser is a wise investment here too.

The most common use for polarisers is to maintain detail in blue skies; they’re most effective when the camera is positioned at a 90° angle to the sun.

If you are deepening blue skies, take care not to over-polarise the sky: you’ll create an unnaturally dark sky with uneven tones. Without getting technical, a polarising filter simply absorbs polarised light, which is how it can achieve the various effects it’s capable of.

Polarising filters are essential for landscape photography because of all the things they can be used for as well as improving blue skies. They can reduce or increase reflections, remove glare, increase saturation, and even be used as a low-strength ND filter, since they can reduce exposure by up to 1.5 stops depending on their rotation. Quite often in landscape photography, you’ll be faced with situations where two or more of these characteristics come in use in a single shot.

hoW to use a polariser

To use a polariser, simply attach it to the front of your lens; if you’re using a drop-in system, use the polariser designed for the filter holder. Once the filter is attached, simply rotate it while you look through the viewfinder or use Live View until the desired effect can be seen.

If you’re using screw-in filters, make sure that if you have filters stacked on top of each other, the polariser is at the top/front of the stack. Screwing another filter onto the polariser will likely rotate the front part of the polariser and change the effect.

Another point worth noting is that if the front of your lens rotates when the camera autofocuses, you will have to autofocus on the desired point, switch the lens to manual focus to lock the position, and then carefully rotate the polariser. Generally speaking, it’s kit lenses that rotate when focusing.