I was considering writing a short blog post about the virtues of using Polarizing filters when, while photographing in the Olympic National Park toward the end of August (see my previous post “Return to the Olympic Peninsula” ) I was shooting at Sol Duc Falls and I moved my camera from vertical to horizontal and took a couple of shots. When I checked the image on the back of the camera (yes – I am a chimper!! I can’t help myself!) I noticed that I had forgotten to re-adjust the Polarizer, resulting in an image that was not polarized at all. The resulting image is shown in the left half of the image below, the right half of the image is the polarized version. This serves as an excellent illustration of why a polarizer is an essential tool in the camerabag.
This was a very fortunate mishap as it provides a perfect example image for the post.
Note the glare on the water, the rocks and the foliage as well as the lack of saturation in the unpolarized half of the image. It is important to note that this image was not taken in direct sunlight – the sun was very low on the horizon and the scene was in shadow, however notice the amount of glare still present in the image when comparing the left-hand and right-hand images above. Both images have the exact same treatment in Adobe Camera Raw.
If interested, you can view the complete correctly polarized image here: image: Sol Duc Olympic NP #03 or my complete online landscape gallery here featuring more images of Sol Duc Falls and the Olympic National Park.
The polarizing filter is an absolute must if you are photographing any type of natural scene or landscape outdoors. The effect CANNOT be simulated in software such as photoshop! Let me say that again: the effect CANNOT be simulated in software such as photoshop!
So, let’s take a step back and start from the beginning. How do we use our polarizing filter? Firstly, some basics that you must know about polarizers to use them successfully:
1. They have the most effect at a 90 degree angle from the location of the sun and progressively less affect as that angle is reduced or increased.
2. They reduce the amount of light reaching your sensor by up to 2 stops and therefore require adjustment to your exposure settings which may effect the aesthetics of your image. A side-effect of this is that, they may be used at a pinch to lower exposure so you can shoot at a slower shutter-speed, similar to a 2-stop ND filter.
3. Due to item 1 above, they are very difficult to use with wide-angle lenses (24mm and wider) due simply to the angle of view covered by these lenses and provide uneven polarizing effect when so used. Full polarized setting when using a wide-angle lens is seldom satisfactory.
4. Use them to darken blue sky and make clouds “pop”
5. Use them to remove glare from foliage and water (as in the example above)
6. They increase color saturation
7. The Polarizing effect may not be simulated by software (this is worth repeating for a third time!) - this is something you must do in the field.
The filter itself consists of 2-rings of glass, one fixed to the filter thread on the front of your lens and the other able to be rotated, enabling you to “dial-in” the polarizing effect. Note that because these filters consist of 2- rings, rather than the single filter ring used on many other filter types (such as warming filters), the filter can be quite thick and can cause some vignetting in the corners of the image (especially when using them on a wide-angle lens). It is possible to buy special “thin” filters to help avoid this vignetting, but these thin filters normally do not come with a front filter thread which may be a disadvantage if you ever need to stack filters.
The filters come in 2 basic types linear and circular. If you are using an auto-focus camera and want the auto-focus to continue working with the filter mounted, you must use a circular polarizer as a linear one will not allow the auto-focus to work.
Like all equipment in photography, you get what you pay for, so buy the best you can afford. I am currently using B+W filters, the one on the left in the image above is an 82mm diameter “thin” filter used occassionally on my 16-35 f/2.8 super wide-angle zoom, the one on the right is a 77mm diameter Kaeseman filter used on my other lenses. The Kaeseman has a superior foil to other polarizers and is completely sealed for use in adverse conditions.
To determine if a polarizer will help in a particular image situation, you can hold the filter up in front of your eye and turn it to see if it is having any effect on the scene in front of you. If it does and you like the effect, you can then add the filter to the front of your camera. Be wary of any unwanted vignetting caused by adding the filter. With the filter on your camera lens, the actual amount of polarization can be varied by turning the outer ring of the filter. Just a quick caution here – it is best to always turn the outer rim only in the direction that you use to screw the filter on to the front of the lens so you do not inadvertently unscrew the filter. You can vary the effect from no polarization at all to maximum polarization, please note that the maximum setting may not always be the ideal setting for your situation, there is such a thing as over-polarization. For example, when using the polarizer to darken the sky the result may be a very unnatural almost-black sky or when photographing moving water (such as a waterfall) and using the polarizer to remove the glare, the effect may be water that appears to not be moving at all if maximum polarization is used, some small amount of glare may be preferable. You must exercise some judgement as to how much polarization is appropriate in any given situation and dial the effect in to taste!!
So, attach the filter to your lens and adjust the exposure to compensate for the loss of up-to 2 stops of light, dial-in the polarizing effect, keeping in mind the effect that you are trying to achieve so you don’t over-polarize as described above, compose the image and take the shot. Then always check the results by looking at the image on the back of the camera at 10x magnification and inspecting the histogram. If necessary, re-shoot the image.
It’s time to get out and make some images – happy shooting!
















