Polarisers are one of the few filters that still hold an advantage for digital cameras. Pretty much everything else can be done these days much more easily in post. Even the effect of neutral density filters can be simulated – although it’s still not quite the same. Polarisers are common amongst landscape photographers, although not so much with portrait photographers. But they can be very useful, as the Koldunov Brothers demonstrate in this video.
As I mentioned, polarisers are pretty common filter amongst landscape photographers. They help to remove reflections from lakes and rivers. They make trees and leaves appear more green for the same reason. And they also help to darken down and saturate bright blue skies. For portraits, the principle is similar to that of foliage.
Essentially, as far as portraits are concerned, polarisers remove the specular highlight reflections from the skin.Polarisers are used quite commonly for video, but not so much for stills. Removing the specular highlights can help to reduce glare from direct lights, and also reduce the contrast required to capture the shot. you’ll notice in the comparison below, it also helps remove some reflection and increases saturation in the hair, too.
But, removing those specular highlights can have some negative effects, too. Specular highlights are part of what allow us to define shape and form and depth in a 2D photograph. They help to convey that third dimensions where none exists, giving your subject a flatter, wider appearance.
It can also have a tendency to make skin look soft, almost velvety. I saw numerous scenes out in the desert during Breaking Bad where I could see obvious use of a polarising filter, as the skin wasn’t reflecting the sunlight and environment around it. Obviously, though, they had to use a polariser to pull down the brightness of the sky and prevent it from blowing out to pure white.
It’s a filter I commonly use myself for video, but it’s something one has to be careful with. Fortunately, polarising filters aren’t a binary on-or-off switch. They offer varying degrees of reflection reduction between their two limits. So, find yourself a happy medium that helps to reduce the glare, but doesn’t eliminate reflections from the skin completely.