You know those pictures where the clouds jump out and almost slap you in the face? Or the images of water so crystal clear it’s like you could drink it? Did you think that was some Photoshop trick or the type of lens the photographer was using? Well it’s not. You too can achieve dazzling skies with punchy clouds, reflection free water and not even touch a Photoshop action or buy a new lens. All you need is a polarising filter.
Polarisers come in a couple of types; Circular (sometimes referred to as a CPL) and linear. I could go into the reasons for each, but don’t have space, so basically, choose a circular polariser every time (they are the most common).
In very basic terms a polariser will remove light reflected off a surface. So reflections on water and glass are removed or at least cut down. This makes car windows look clear and you can see into the bottom of a rock pool. If you want a refection, don’t use a polariser.
Polarisers also have the effect of cutting down glare on foliage, and adding punch to a sky as they remove light reflecting off particles in the atmosphere, so they are an essential for landscape photography. So if you were wondering why your landscapes are no where near as good as Sarah on that Facebook group, it could be just as simple as adding a polarising filter.
Out of all the filters on the market, a polariser must come in 2nd place to a UV filter. I use them for landscapes, portraits, and wildlife photography when I don’t want any reflections. They do cut out some light, but a camera will automatically adjust for that.
How to use
Using a circular polarising filter is easy and you don’t need to understand what it’s doing to see the results. All you do is twist it. At some point in the revolution the polarised light being reflected off the surfaces will be cut out. As if by magic any blue sky in the shot will deepen in colour, a pond or stream will become clear (unless the water is turbid) as will reflections in windows, spectacles and on wet surfaces. Twist the filter some more and they reappear. Where this is depends on the position of the light source (normally the sun) and your angle to it.
Some filters have a triangle or a dot which you turn towards the sun, but in practise this is not necessary as the effect of the filter is obvious through the viewfinder and on liveview.
Like everything in life, do not go for the cheapest, but you don’t need the most expensive either. A good quality polarising filter should not distort or reduce the quality of your final image. Cheap ones will disperse the light a fraction and reduce overall sharpness.
Personally I use Hoya filters, but any of the well known brands produce good quality filters, which allow the optical quality of your gear to shine through.
You can buy filters for the size of lens you have and they screw into the filter thread on the front. These tend to have a fixed back part and a rotating front. Filter system types are usually just one filter that you rotate in the holder fixed to the lens. There are pros and cons to each system. If you have a lot of lenses, the filter systems are a good idea as you only need one filter to cover your lenses. If you only have one lens, then a single filter is all you need.
Of course if all you want to do is make a sky bluer and you post process your images. Image processing software can make a sky deeper in colour. What software cannot do is remove reflections, and I am not talking just from glass or water. Any reflective surface such as leaves, eyes, sweaty skin, damp rocks. Anything that can reflect light a polariser will make it look better. That’s why I have a polariser for every one of my lenses and I use them all the time.
I even use them for filming as a way to reduce light and getting a better shutter speed and to punch the colours back into my footage.