What’s a polarizing filter?

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by David Em
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A polarizing filter is placed in front of a camera lens to reduce brightness, reflections, and glare. It’s an essential tool that you need.

Hand holding a polarizing filter and pointing it at the sky.
Photo courtesy of Canva.

What’s a polarizing filter?

A polarizing filter is also known as a polarizer, and it’s a circular piece of glass placed in front of your camera lens to reduce brightness, haze, reflections, and glare.

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The photographic filter is also commonly used to darken bright blue skies. Polarizing filters are most popular among landscape, architecture, and car photographers.

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Unwanted glare can ruin a photo. That’s where a polarizer comes in handy. It allows you to correctly expose most of the image in one shot.

Photographer with text overlay.

How it works

Whether you’re taking photos indoors or outdoors, polarizing filters work incredibly. How it works, comes down to the way light moves.

Waves of light move in many different directions. So, polarizing filters only allow light waves to pass through if it’s moving in a certain direction or angle.

All other light waves are partially or fully blocked. This is how reflections and glare are reduced or eliminated.

The effects of a polarizing filter are one of the only things that can’t be replicated digitally. That’s why they’re such an incredible tool.

Different types

Hand holding polarizing filter showing the Seattle skyline.
Photo courtesy of Canva.

Linear and circular polarizing filters are the two main types. Despite their names, they don’t refer to the shape of the filter.

Instead, it’s about what happens to the light waves as they pass through the filter.

Both types of polarizing filters do the same things, reduce reflections, increase contrast and saturation.

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Linear polarizing filters have a single polarizing layer. While it does the job most of the time, the main problem with it is cross-polarization.

If you have an SLR or DSLR, the mirror can cross-polarize the reflecting image. It may also lead to a blacked-out image, along with metering issues.

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Circular polarizers (CPL) contain a linear polarizer. However, it also has another layer in the filter called the quarter-wave layer.

The additional layer repolarizes the light, making it a better option and fine to use with any camera.

When and how to use it

Person holding a gimbal with a camera and polarizing filter attached.
Photo courtesy of Unsplash.

Regardless of the type of photography you do, you’ll benefit from a polarizing filter. While you’ll lose a stop or two of light, it’s worth it.

Anytime you’re dealing with reflections or haze, use a polarizer. It’ll also enhance the saturation and contrast in your image.

To use a polarizer, all you need to do is screw it onto the front of your camera lens. As you screw it on, look at the live view or through the viewfinder to see how things change as your twist it.

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Once you install the polarizer, adjust all the other settings to properly expose the image. Again, you’ll lose a stop or two of light. So, keep that in mind as you’re adjusting the exposure.

Polarizers work best when you’re shooting at a 90-degree angle from the sun. They’re not meant to be used when you’re facing the sun.

If you’re planning to photograph the sun in the sky, a sunrise or sunset, remove the polarizing filter.

When not to use it

Polarizers have many benefits. However, you can’t use them all the time.

Since a polarizing filter reduces the brightness, you need to compensate with the shutter speed, aperture, or ISO. It’s not possible to do so in all situations.

For example, too slow of a shutter speed can lead to a blurry photo. In this case, it’d be better to remove the polarizing filter.

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Another drawback is that it can lead to an unequal and unnatural appearance.

It’s most common with wide-angle lenses and blue skies. A polarizer can cause the sky to shift from dark to normal, which doesn’t look realistic.

So, the best course of action is to only use a polarizing filter when there are reflections or haze.

Another time to skip the polarizing filter is if you’re using a cheaply made one. High-quality polarizing filters, such as the ones made by B+W, are incredible.

However, polarizers made with poor quality will smoothen your image and mess up the colors. It’d be better to not use one at all than to use a poorly-made one.

Conclusion

A polarizing filter is an essential tool you need to have in your camera bag because it reduces glare, reflections and leads to beautiful and well-exposed images.

It works by only allowing light to pass that moves in a certain direction.

Once you start using a polarizing filter, you’ll wonder how you shot without one. The results are stunning.

Featured image courtesy of Canva.

About David Em

David Em.

David Em is the founder of Portraits Refined. He’s a published portrait photographer dedicated to helping photographers develop skills, capture incredible photos, and build successful businesses.

About Portraits Refined

Portraits Refined (PR) is a media company that publishes the latest expert-backed portrait photography tips, in-depth camera gear reviews, and helpful advice to grow your photography business.

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