POLARISING FILTERS: PROS AND CONS
Circular polarising (CPL) filters are an item that many photographers buy, without really knowing how or when to use them. So here’s a quick look.
Without getting into the science, polarising filters reduce glare just like polarised sunglasses. They will deepen the colour in a sky, reduce reflections off wet and shiny surfaces, and can be great for bringing clarity and vibrance to scenes that might be hazy or washed out due to excessive glare. A polariser will often be used for landscapes, but I find they can be great for rainforests and waterfalls too as they take the glare off shiny leaves and wet rocks. Once screwed on to the front of your lens, the front element continues to rotate, allowing you to increase and decrease the polarising effect to suit your taste. It is possible to over-polarise until your sky becomes very dark, so the ability to dial it back a bit is important.
Polarisers are not suited to all types of photography though, and in many situations you DON’T want one on your camera. It’s important to realise that polarisers are made of shaded glass so they reduce the light…forcing you to use slower shutter speeds or higher ISO to take your pictures. So if your polariser isn’t helping, it is best to remove it.
So when don’t they help? Well, they don’t do much in the very early morning or late afternoon when the light is very soft. And since this is when I like to do most of my landscape work, I will often be working without the polariser. They don’t make much difference when looking directly towards the sun, or directly away from the sun, but they can be effective on other angles. So if the sun is in your face or behind you, the polariser might not do much at all. But if it is on your left or right, it could make a real difference. And of course for anything that really needs a fast shutter speed I take it off. I hardly ever use it for wildlife photography.
So to make a long story short: polarisers are great for certain subjects and I recommend you get one. In some situations it will truly enrich your photography. But if it is not helping you, it is actually doing harm, so take it off when you don’t need it. If you buy one, don’t just put it on and leave it there. Experiment with it at different times of day and with different subjects and you will soon get a feel for how to make your polariser work for you.