Today and tomorrow, my posts will discuss polarizers: what they are, when they are useful, and some lesser-known tips on how to use a polarizer. These posts are in response to a misguided photographer who recently told a student in one of my classes that polarizers don't work at sea level. That's a new one!
There is one phenomenon that works 100% of the time, without fail or faltering. That is, when I teach photography classes to beginners, at least one of the people in the class will not be able to focus when we try an in-class shooting assignment. They will complain that they can't focus and their shutter speed is so low that the pictures are blurry. Seriously, it's like clockwork. Truly amazing.
Why is it that at least one person has this problem? It's because the dude at the camera store told him that he needs a polarizing filter, so he put it on the one lens he owns and never takes it off.
Don't get me wrong. I love polarizers! But if you don't know how to use it properly, it will be a severe hindrance to your photography. Let's learn how to use a polarizer the right way, and when to not use it at all.
The problem with polarizing filters is that they block about 1.5 stops of light from reaching the camera. To compensate for the reduced light, your DSLR will compensate with a slower shutter speed–hence the blurry pictures. It also prevents many slow lenses from focusing in dim situations. So the first lesson to learn in using a polarizer is that it should be taken off until it is needed, and never left on the lens for convenience.
What do Polarizing Filters do?
Polarizers accomplish three main objectives for photographers. First, a polarizing filter cuts out the glare in a scene. Mid-day glare on plant leaves can be removed by simply using a polarizing filter. The glare on water can also be removed by using a polarizer. Heck, it can even be useful for cutting the glare off a bald man's head.
The second main purpose of a polarizer is to saturate colors. This is especially handy when shooting landscapes which are drowned out with harsh lighting. While this type of shooting situation will often result in desaturated colors, a polarizer can remedy this.
The last thing a polarizer can do is improve the skies in your photography. Polarizers can deepen the blue sky and brighten the white clouds to create stunning and dramatic skies even in bright sunny conditions. This is the main reason photographers use polarizers.
Tomorrow's post will be Six Tips for Using a Polarizer.