The most under-used item in your camera bag is a filter – the polarizer. This one filter can make such an incredible difference to your photographs that it is difficult to leave it off the front of your lens. Colors are richer to start with, which is a definite plus. But there are some negative issues as well.
These filters are different from most others in the fact that they are made up of two distinct elements. There is an outer ring that rotates the outer “glass” relative to the inner element. This increases or reduces the degree of polarization to allow an endless range of polarized effects from one filter.
Now there are people who think that all a polarizer can do is let you see ladies legs in swimming pools. This is merely a minor property for this extremely versatile filter.
What you have to understand, with these filters, is that they remove reflections that come from any surface, not just water. The reason you cannot see through some windows is because of reflected images on the surface of the glass. The reason some tree leaves appear to lose their color is reflected light from the sky above. Likewise, a shiny red boat is reflecting light from the sea or the sky.
One of the traps for young players is that because you know the grass is green, you see it as green when you look through the camera lens. The ability to look in a discriminating way is one of the real secrets of photography, let me assure you.
Look again at the green grass scene in the viewfinder. The green grass is really a mixture of green, silvery reflections, dark shadows and pale green shoots. Put the polarizing filter on and slowly rotate the outer ring. Suddenly the silvery reflections disappear and become a deep, solid green color. The grass is now made up of green, dark green and pale green. This green will really leap out at you and smack you fair between the eyes!
Your next beach scene when taken with a polarizer will really amaze you. Again, slowly rotate the outer ring on the polarizer. Look critically through the viewfinder and you will see the sky take on a much deeper color to highlight the white clouds. Keep turning that outer ring and the sea will change to a deep blue to green luminescent hue. The end result is at your command. Try taking the same shot this weekend, but with varying degrees of polarization and see the difference in the final images.
Another shot to try with or without polarization is photographing a reflective, shiny object like your family car. Again, by looking critically through the viewfinder you will see what happens when you remove the reflections from the paint work.
So, if the polarizer is such a wonderful bit of gear, why do we not make it a standard piece of equipment on all cameras? Well, like everything, as I mentioned in the first paragraph, there is a downside as well as the upside. In the case of the polarizer it does its bit of brilliance at the expense of the amount of light that gets through to the electronic image sensor. With most polarizing filters you will lose about one and a half stops of light. What this means is that the shutter speed will be at least twice as long to record the same scene, or that the aperture will be twice the size. This means that you are more likely to get camera shake effects and suffer from lack of depth of field when using the polarizer. Another drawback is that the light drop upsets your flash settings, so compensation has to be made for night shots.
However, if you haven’t got one – get one this weekend and see the full bodied difference a polarizer can make!