Take Off That Polarizer

High shutter speed, and not a polarizer captured this Humpback Whale's tail

It never fails. Every time I teach a photo workshop, I notice that at least 25% of the participants have a polarizing filter on their lens and they never take it off. Here on board the National Geographic Explorer in Antarctica I’ve been using the phrase “Just because we’re in a polar region, you do not need a polarizing filter!” This onslaught of polarizing filters must be a result of camera sales people trying to sell more gadgets to their customers with the promise of better images through polarization. Yes, polarizers do have their place in photography, but definitely a limited place.
I’ve always believed that putting a filter in front of your lens deteriorates the sharpness of your glass and since polarizers use two pieces of glass the results are worse. Also, the loss of 1.5 to 2 stops of light is quite significant; especially if you are trying to shoot penguins, seals and whales from a moving ship and need a high shutter speed.
What situations warrant the use of a polarizing filter? If you shoot a landscape with blue sky and puffy clouds and you want the sky to look dramatic, you can use your polarizer but keep in mind that it is only effective if the sun is 90 degrees off your subject. Even then, I think that this look is a bit old fashioned and should be used judiciously.
A polarizing filter will also eliminate the reflections that occur if you shoot through glass. Use one if you want to photograph the Christmas windows at a big department store. If you need to shoot copies of art work that have a high gloss finish you should also polarize your light source in addition to using a polarizing filter.
When you are shooting scenes that include a large body of water, a polarizing filter will eliminate the glare that can occur from the sunlight. Keep in mind however that sometimes glare can make the water look moody and more realistic. Some photographers use the polarizer when shooting fall leaves to help saturate color. However, if you want a reflection of trees and leaves in a lake, you will need to remove the filter or you will lose the reflection.
If you plan on buying a polarizer spend a little extra money and get a good one that won’t compromise your high quality optics. Always test the filter in the store with your widest lens to be certain that it won’t cause vignetting. The polarizer is a thick filter; if you anticipate using it with a wide lens look at the special, thin polarizers made for wider lenses. Never use a polarizer to protect the front element of your lens. Get a UV, haze or skylight filter for that purpose
I do carry a polarizer with me, but I only use it when I think it will help make a better image. In many instances the use of a polarizer is a subjective decision and is based on the type of image you like to shoot.
But if you need a good shutter speed to shoot something moving and the situation doesn’t warrant polarization, take the filter off and get a sharp picture. More equipment doesn’t always make a better photograph.