Why use a CPL or polarising filter and what is a polarising filter?

Have you ever asked yourself what is a polarising filter or struggle to know why or when to use one?

What a polarising filter? A polarising filter or CPL as they are also called is a usually a round filter that screws onto the front of your lens or fits in your filter holder.

Which bring us to what does it do and how do use it…

A CPL will…

1. Help reduce reflections.
2. Help saturate your skies and forest scenes.
3. Add about 1 to 2 stops of light reduction.

Reflections

A CPL filter will help kill off reflections in an image, this can provide us with several awesome effects.

Water and Lake photography

You are at a lake and there is this gorgeous branch in the water that slowly slips below the water-line and leads you towards your subject for this example let’s say a snow-capped mountain (if we are going to pick an example why not make it epic). You are standing there and you can see this with your naked eye when you move around but when you take the shot the camera just captures the reflection on the water and you loose that beautiful leading line in your shot or those precious little details below the water-line.

So you pop on your CPL and you twist it to the right polarisation (damn it a technical word slipped in there but don’t worry about it), lets try that again… you turn the cpl so you kill off the reflection and now you can see through the water to all that beautiful detail below. You can also play with the effect to just get the right amount of transparency sometimes less is more :-). So that’s the first scenario.

Cars and Shiny objects

The second scenario is you are photographing a car that your friend is putting up for sale and it’s all nicely polished and super shiny. When you take a photograph of it you get all those annoying reflections ruining your shots… now again pop on the CPL and turn it till the reflections on the side of the car are more or less gone. When I saw turn it what I mean to do is to look through your view finder and rotate the cpl on your lens as you do, you will see a lot of the reflections magically vanish, now they won’t all vanish but you can select the ones you want to kill off by rotating the filter.

Street Photography uses

Scenario three, you are out to meet a friend in a coffee shop and you see them sitting by the window sipping a cup of coffee and suddenly you think wow what a shot that would be… The reflections in the window create a sort of a double exposure effect in your short. So, you can see your friend sitting having the coffee and you can also see the reflected street details in the window. What works really well here is if they are staring out into the street it’s like they are bringing the image to life as you see what they see even though you are looking the wrong way, nuts isn’t it…

When you take the photograph though the reflections of the street are probably going to be too powerful and they could ruin the shot, pop on your CPL and rotate it slightly so you can get this amazing mix between just the right amount of refection and your subject to create a real work of art. Can you see where I am going with this? This has gone from a casual shot to you now telling a compelling story and isn’t that what photography is truly all about?

A polarising filter is not just something that’s handy, it can be vital at the best of times and we are still only on the first advantage of using a CPL and it’s reflection killing super powers. So if you thought that was good then read on for some more amazing features of a CPL filter.