CPL filters are popular among landscape photographers. These glass filters reduce glare and reflection and help you capture deep colors, stunning skies, and transparent bodies of water.

Here is what you need to know about how a circular polarizer filter works and how to get the best results when working with light polarization.

What is a Circular Polarizing Filter?

When light waves hit a nonmetallic surface, they typically bounce off and are reflected along a plane that is parallel to that surface. This phenomenon causes glare to appear when light hits an asphalt surface, a mountain covered in snow, or a lake. Polarization can also occur when light is refracted through a transparent surface like a windowpane.

The purpose of a circular polarizing filter is to block these waves that travel along a specific plane. You can adjust it to block waves traveling along reflective planes and capture light from the original source without any glare or reflections.

Why Should You Use a CPL Filter?

A CPL filter is very easy to master, and it’s an affordable piece of photography gear. You should consider adding one to your gear bag because they create an effect that you can’t reproduce through digital editing and help you master reflections.

You can do some interesting things with glare and reflections in your photos, but the truth is that patches of bright light often result in a loss of definition and make colors look somewhat faded. You can add a CPL filter to reduce unwanted light and work with a wider range of sharp colors, enhance contrast, and get better details.


How Does Using a CPL Filter Enhance Your Shots?

A circular polarizing filter can give your photos a very noticeable look. Your landscape photography will have a professional quality, and details and colors will look sharper and more true to life.

Using a CPL filter prevents common issues like reflections, glare, and overexposure. Some colors and details are closer to the way things look to the human eye since there is less reflective light that is captured by the camera sensor.

filter over flowers

Image by Emilian Robert Vicol (Pixabay License)

A CPL Filter Can Intensify the Sky Color

Polarization causes objects that are far away from you to look faded when you shoot them. There is a lot of space filled with light waves, which results in your camera sensor capturing a lot of noise and failing to get a sharp photo of faraway objects. The same thing is true when you capture the sky.

Removing that noise with a filter will result in sharper images with deeper colors. Sky color will look darker and richer, and you will get more sharpness for faraway objects. A CPL filter is a common option for landscape photography because they give skies a deep blue hue.

snow in a field

This image by Alain Audet (Pixabay License) shows how you can enhance sky color and get sharp details for surfaces like snow.

A CPL Filter Can Cut Reflection

Scattered light is an issue when capturing a scene with a large reflective surface. You will probably encounter this issue when photographing a lake, a road, a beach, or a surface covered in snow.

This causes parts of the picture look blurry and can make colors look faded. With a CPL filter, your camera sensor can cut through reflected light and capture the surface itself rather than the light that bounces off it. You can, for instance, capture transparent water instead of the sky reflected in a body of water.

water over rocks

This shot by Couleur (Pixabay License) illustrates how you can capture the transparency of a lake with a CPL filter.

A circular polarizing filter can give your photos a very noticeable look. Your landscape photography will have a professional quality, and details and colors will look sharper and more true to life.

Using a CPL filter prevents common issues like reflections, glare, and overexposure. Some colors and details are closer to the way things look to the human eye since there is less reflective light that is captured by the camera sensor.

How Do CPL Filters Work?

A CPL filter is a glass attachment with two layers. There is an external layer that acts as a horizontal filter and a second layer that is a circular polarization filter.

You can adjust the horizontal filter to block light coming from a specific plane. Waves from that plane will bounce off the filter, limiting the amount of light the sensor captures. The waves that make it through the first layer of the polarizing filter are polarized again by the second layer of the filter.

You can find a wide range of glass filters that fulfill this purpose. You can find gear that is small enough to fit a phone camera, as well as a different size of glass filters you can add to a photography cart.

Types of Light Polarization

Linear polarization is the most common type of polarization you will encounter in nature. It occurs when waves are reflected along a single plane. That plane is usually parallel to the reflective surface. A common example is the reflected sky and glare you can observe on a body of water.

You can also encounter circular polarization. Waves follow two perpendicular planes and have the same amplitude. This phenomenon can occur underwater, and bioluminescence from some insects can cause circular polarization.

There is a third type of polarization that isn’t common in nature. Elliptical polarization occurs when waves follow two perpendicular planes but have different amplitudes.

filter over plant

Image by Emilian Robert Vicol (Pixabay License)

CPL Filters and Modern Cameras

A traditional polarization filter can cause issues with modern cameras because they use a single layer of glass for linear polarization.

If you use a camera with a digital sensor, you should use a circular polarizing filter. It will have a second quarter-wave plate that transforms light into circularly-polarized light. This type doesn’t cause any issues when using features like autofocus.

When to Use a CPL Filter

A CPL filter is a must-have item for landscape photography if you want to capture scenes with large reflective surfaces. You can also use it to limit refraction when capturing a shot through a window or transparent object.

You should use one if you want colors to look deeper and darker, especially in the sky, or want to capture the transparency of a lake or ocean. You should also use it if you want to get a matte effect when capturing a reflective surface.

Even though circular polarizer filters are common in landscape photography, you can use one to enhance the results of a portrait photography session.

When shooting portraits outside, natural light can cause glare to appear on your model’s skin. Reflective surfaces like glasses or jewelry can become problematic. A CPL filter will effectively eliminate these issues, besides helping you capture amazing backgrounds.

How to Get Good Results with a CPL Filter

In order to remove polarized light, your CPL filter is going to limit the amount your sensor captures. You need to adjust it to get rid of unwanted reflected waves while getting enough exposure and find the right angle for your shot.

There are very few instances where you should use the full polarization effect of your filter. That setting will filter too much and result in a dark image. You should adjust the external element to block light from the plane that is causing glare and reflections without limiting exposure more than necessary.

You might need to increase the exposure time to capture more and prevent your photo from looking too dark. Increasing the exposure time while using a polarizer filter will help you get rich and saturated colors.

A common issue you might experience when using a polarizing filter is to end up with a photo where the sky looks too dark. CPL filters can create a sinister effect by darkening some areas of your image. The key is to adjust them and the exposure time to find the right balance.

Top Things to Avoid When Shooting with a CPL Filter

Using a wide-angle camera lens isn’t recommended. With a wide-angle camera lens is difficult to get an even effect when using a CPL because a wide-angle lens can limit exposure in an area of your image more than in another. With this lens, it’s common to end up with photos where the sky looks darker in one area.

This effect will be more noticeable if you shoot with a wide-angle camera lens, and you might end up with a photograph that has a sinister feel to it due to the darkened effect. This is a common issue when taking pics with a phone since a lot of Smartphones come with a wide-angle lens. 

mountains and cloudy sky

This shot by Pexels (Pixabay License) features sharp details and deep colors, but the sky looks dark.

Just like a wide-angle lens, you should also avoid using a polariser filter in low light settings and during overcast days. The purpose of these filters is to reduce how much your sensor absorbs.

You will probably end up with an underexposed photo that doesn’t look good at all when shooting in low settings. Note that you can compensate for this problem to some extent by increasing the exposure time.

sunset in over a lake

This shot by Julius_Silver (Pixabay License) is an excellent example of the kind of effect you can’t capture with a CPL filter.

Using water in your shots can create an aesthetic effect, but a CPL filter will make that effect difficult to capture. For instance, you won’t get the wet and glistening effect of raindrops with one of these filters.

Sun position is a factor that can limit your use of a CPL filter. You won’t be able to get the desired effect when the sun is low on the horizon or directly behind you.

Conclusion

A CPL filter is an interesting addition to your gear bag because it creates effects you can’t obtain through digital editing. You can get stunning results once you learn how to adjust it and understand how the sun position affects the outcome of your photos, and a CPL filter is one of the best ways of getting sharp details and deep colors for landscape photography.