Yesterday, we discovered what circular polarizers are and what they accomplish. Today you'll learn six tips for using a polarizer.
Polarizer Tip #1: Polarizers will have little or no effect when used to shoot a setting sun, because the angle is wrong. The effect of a polarizers manifests itself at 90 degree angles to the sun. So if you make a gun shape out of your hand with your forefinger as the barrel and your thumb as the hammer, you can remember how to use a polarizer. Simply point your forefinger at the sun, and you'll know that any direction your thumb can rotate to point to is the correct place to point your camera with a polarizer. You can change the axis a little bit, but if you deviate too far from 90 degrees to the sun, the polarizer will not accomplish much. Take off your polarizer for sunsets. It won't saturate the colors, it will cause lens flare and ruin the picture.
Polarizer Tip #2: One lesser-known tip for using polarizers is they are fantastic for shooting rainbows. Most people say not to use a polarizer for rainbows because it will make the rainbow disappear. After all, rainbows are caused by glare when the sun's rays hit a pocket of moisture. Don't listen to the people who teach this, because they don't understand that if the polarizer is spun the opposite direction, it can actually INCREASE the amount of glare in a scene more than the natural eye sees. This makes the rainbow even more clear and colorful.
Polarizer Tip #3: There are two elements in a polarizer. The front element needs to be rotated to control the strength of the polarizing effect. So look in your viewfinder and spin the front element until you see the correct amount of effect. It can be tough to determine how strong to make the effect and most people, in my opinion, go too far. My key for using a polarizer is to turn it to as strong as it will go, then back off just slightly. This should be about right. When you get the image on the computer, you'll see it's usually a bit stronger than it looked in the optical viewfinder.
A good example of too much polarization is the many picture's we have all seen of a canoe floating in a crystal clear mountain lake. A polarizer is used for this shot to remove the glare, but if you remove ALL the glare and don't leave just a hint, it looks strange like the canoe is floating in the air. It's a bit distracting. The picture to the left is another example of over-polarizing a photo.
Polarizer Tip #4: Keeping a polarizer handy can be useful as a poor man's neutral density filter. Remembering from yesterday that a polarizer cuts about one and a half stops of light, you can use a polarizer to cut out some light when you're in a pinch. Is this ideal? No, but it's better than not getting the shot at all!
Polarizer Tip #5: Don't buy a cheapie. The cheap polarizers use aluminum rings, which can cause it to bind to the lens. Good luck getting it off without damaging your lens threads. Also, cheap polarizers are not multi-coated. This can cause ghosting, lens flare, reduction in contrast, serious illness, dizziness, and in some rare cases–death.
If you're looking for a good polarizer, make sure you buy the one that fits your lens diameter. Check your lens. It will say whether it's 58mm, 77mm, etc. Then buy a polarizer in this size. It doesn't matter whether you shoot Canon or Nikon, they all fit the same threads as long as you have the right size. I recommend the Nikon polarizer in 77mm, in 72mm, or in 52mm. Just look on the front of your lens at the tiny lettering to see what size it is.
Polarizer Tip #6: Most people avoid using polarizers for panoramas. Because such a wide angle will alter the strength of the polarization effect as you vary your view from 90 degrees to the sun, the photo often looks very unnatural; however, I have had success in using polarizers for panoramas by reducing the polarization when 90 degrees to the sun, then slightly making it stronger as I leave that angle for the wider shots. It has worked for me in the past, but it is very tricky to get right. If you aren't this adventurous, maybe you'd be better off with bite-sized composition.