A polarizing filter is most often used to darken blue sky or to reduce reflections. These filters are very useful in landscape photography. The effect that one of these filters has depends on the direction of the light in relationship to the orientation of the lens.
Filters that rotate are a must so that you can adjust your filter to the direction of the light.
Because they will reduced the reflections on leaves and foliage, your photo will have better saturation of colors. Look at the outdoor picture below.
This was a real quick photo assignment I gave myself to illustrate the effect of a PF (polarizing filter). I grabbed my Canon 5d DSLR with the 24-105 zoom lens attached and the filter from my camera bag.
My lovely bride of 27 years was napping on our hammock. Of course while in a hurry, I grabbed a 55mm filter for a lens that needs a 77mm filter. In the photograph on the right, I simply gripped the PF by it's edges and held it flush with the front of the lens.
Look at the difference! Not only did the sky turn a beautiful blue, but we also got more color saturation in the foliage.
After I finished taking pictures of my sleeping wife, I turned to my neglected fish pond. I used the same creative photography technique of holding the PF in front of the lens.
Here you can see that the filter reduced the reflection from the blue sky.
In the photo on the right, you can see the leaves of the lily beneath the surface of the murky green water.
Had the water been clear, you would have been able to see the bottom of the pond, where the fish hang out, in the photo where the filter was used.
What if you don't own a PF?
One way to cheat is to use sunglasses that have polarizing lenses. This will only work with "point and shoot" or smaller cameras where the lens size is not big like a DSLR lens.
Make sure the sunglasses's lenses are clean and free of scratches. Also realize that sunglasses don't have the same optical quality as a professionally manufactured photography lens filter.
The best part about using a filter that polarizes the light is that you can see what the effect is going to be before you take the photograph. You can hold the PF up to your eye, or hold it up to the lens and look at your digital camera's LCD screen or viewfinder.
Of course the best way to high quality is to use one that screws onto your lens. This is an option if you have a DSLR and an option for some point and shoot digital cameras as well.
Look at the dramatic difference in the window reflections of these two photos below of Charlotte NC buildings. This top photo was taken with no polarizing lens filter.
Compare the reflections on the right side of the building on the right with the photo below. Look how dark the windows appear in the absence of reflections.
This is a case where I actually prefer the non-polarized lens photo more. The reflections on the windows in the window add some dimensionality by making the right side of the building brighter.
You can see that using the polarizing filter does add some contrast and saturation to some of the shadows and mid-tones in the photograph.
For more Charlotte NC Photos go to Charlotte NC Photos.
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These filters come in all sizes and also several different levels of quality.
In addition to how well the filter rotates is the quality and number of lens coatings that have been applied to each filter.
You can learn a lot about these polarizing filters by reading reviews about Polarizing Filters on Amazon.