There are many tools in an outdoor photographer’s bag of tricks that help turn simple photos into works of art. Some seem insignificant but are vital to nearly every image. For the outdoor photographer, a good circular polarizer is just such a tool.
What a Circular Polarizer Does
The following explanation of how a circular polarizer works is crude, but will suffice to explain why it’s an important filter to use. You can also visit canont6i.com/best-lenses to understand how to capture such image using your Canon camera.
Reflective surfaces, like water and glass, cause a lot of polarization. This in turn causes glare, blocking color and details. Water and glass are not the only things that polarize light. Pretty much everything does, just to a lesser degree. Plant leaves, flower petals, grass, buildings…even the sky, affects light in this way. And even a little polarization reduces color saturation and perceived detail. This is where a circular polarizer becomes so useful.
When light is polarized, its wave is changed into predictable patterns, linear and circular. Linearly polarized light waves from side to side. Circularly polarized light moves in a corkscrew pattern, and can be either clockwise or counter clockwise. Linearly polarized light creates the glare and reduces saturation in photography. When light passes through a circular polarizer, the linear polarized light is changed to a circular polarization; in affect filtering out the linear light.
There is one thing to note, however. Circular polarizers don’t work on light reflected from metal surfaces. The reason is light polarized from metal is in a rotation opposite of what the filter creates.
How it’s Done
Circular polarizers are threaded to screw onto the end of your lens, and have two sections. This structure allows you to rotate the filter to gain the maximum benefit available in a given situation. Being able to rotate the filter is important because the closer to a ninety degree angle the sun is to you, the less effect the circular polarizer has. When you rotate the circular polarizer, it allows you to increase or decrease the amount of filtering.
When you are getting ready to take a photograph, make sure the circular polarizer is already on your lens. First, focus until your subject appears tack-sharp. Then, while looking through your viewfinder, rotate the circular polarizer until you find the spot where glare is minimized and colors are richest. Next, take a light reading to set exposure. If you’re using the camera’s built-in light meter, you can set exposure normally and take a picture. But, if you’re using a hand-held light meter, keep in mind the circular polarizer reduces your amount of light, generally from 1 ½ stops to 2 stops. If your meter reading says you need a shutter speed of 1/30, slow down your shutter speed by 1 ½ or 2 stops. If you are new to outdoor photography, or are not accustomed to using a circular polarizer, bracket your picture by taking two more images, one at half a step faster, and another half a step slower.
It’s Easy to Use a Circular Polarizer
That’s all there is to it. In my outdoor photography there’s always a circular polarizer on each lens. When you regularly use one in your work, you’ll be amazed at how much your photography improves.