Introduction to the Camera Polarizer Lens: Why You Should Start Using Polarizing Filters

Polarizing filters can dramatically impact your images, especially if you frequently shoot in natural light. So getting to know how they work and investing in one can certainly be worth your time and money.

What is a polarizing filter?

A polarizing filter, or polarizer, is used to intensify blue skies, brighten or saturate colors, and reduce reflections, glare and haze in images. Similar to other types of lens filters, polarizers fit on top your lens and can either screw into your its filter thread or be used with a filter holder. You then rotate the filter to find the optimum position to separate out polarized light that’s heading towards your camera from a given direction.

Unlike almost every other type of lens filter out there, except possibly for the diffusion filter, a polarizer’s results cannot be accurately replicated in post-production. So although being quite expensive, polarizers really are invaluable.

How does a polarizer work?

So what does a polarizing filter do? When light radiates from a source, it does so in all directions equally. If it bounces off of something, such as water, glass, or any particulates that float about in the atmosphere, it polarizes. Instead of moving off in multiple directions, it tends to reflect at the same angle. This results in a reflection, glare or haze.

A polarizing filter can separate polarized light moving at a particular angle from non-polarized light. To find the optimum position to filter out light coming from a given direction, you rotate the polarizer in front of your lens and choose the best effect for your shot. If you look through your viewfinder or at your LCD as you turn the filter, you’ll see a reduction in glare or an increase in color saturation.

Linear vs. circular polarizing filters

Polarizing filters come in two varieties: linear and circular. “Linear” and “circular” don’t refer to the shape of the filter, but rather to how they modify the light rays that pass through them.

Linear polarizing filters only have one polarizing layer. As a result, when light rays pass through them, they can be cross-polarized by the mirrors in DSLR cameras, which in turn interferes with autofocusing and metering technology.

Circular polarizing filters (CPLs) contain two polarizing layers. The second one, called a “quarter-wave plate,” repolarizes the light that passes through the first layer. While repolarizing the light you’ve just polarized might sound counterintuitive, it remains polarized – just differently. It will no longer disturb the metering or autofocusing processes of the camera. So while CPLs are more expensive than linear polarizers, they do provide better performance.

Circular polarizer | Image by PiccoloNamek (CC BY-SA 3.0)

That being said, CPLs will block some light from reaching your sensor, potentially up to three stops. This means that to properly expose your scene, you’ll need to use some exposure compensation – for example by setting a larger aperture.

ND filters vs. polarizers

If a CPL blocks light from your sensor, can you use it like a neutral-density filter (ND filter) to help control exposure in very bright conditions? Yes, you can. But what you have to remember is that an ND filter won’t have any impact on the colors or any reflections in your scene. If you’re looking to shoot a scene with accurate color reproduction, or with reflections for whatever reason, you’re best off using an ND filter.

The benefits of polarizing filters, and when to use one

Wondering when to use polarizing filters? Ideally, you should use a polarized lens filter when you want to reduce glare or reflection from water, glass or even leaves. If you’re shooting through glass, like a shop or train window, a polarizer can help remove any reflections that would distract the audience. While total elimination of reflections is unlikely, a significant reduction is possible when you use a lens filter for reflections.

If you want to intensify the blue of the sky or saturate colors more deeply, a polarizing filter will help by reducing the direct reflections in a scene. This effect works best on bright sunny days, rather than overcast ones, and when you’re shooting at an angle perpendicular to the sun. Similarly, by reducing the reflections off of random particulates in the atmosphere – for example, water droplets or pollution – you can reduce haze and increase clarity in landscapes and cityscapes. This is especially useful when you’re shooting scenes from a long distance.

The disadvantages of polarizers, and when not to use them

CPLs are brilliant pieces of kit, but they don’t work in all conditions, and under some circumstances, can make your footage look worse rather than better.

For starters, if you’re shooting with the sun directly behind you, a polarizing filter will not have a discernible impact on your footage. If you pan, alteration in the sun’s angle to your camera can result in changes in the degree of polarization.

Although polarizers can reduce the reflection and glare coming from glass and water, they can’t reduce reflection coming from metallic surfaces. The light reflected off metallic surfaces isn’t polarized, so a polarizer has no impact. And while light will reflect off of other surfaces from mostly the same angle, it won’t be entirely uniform, so you won’t be able to eliminate reflection or glare completely.

Using a polarizing filter when you’re shooting around sunrise or sunset or trying to capture a rainbow can work against you. In these situations, you’re usually looking to capitalize on the reflected light and its colors, rather than negate it.

Depending on the angle of the sun to your camera, shooting with a wide-angle lens and a polarizer can produce an uneven effect across your scene. You might find that anywhere facing directly into the sun will appear much darker than areas at 90º to the sun.

Adding another layer of glass in front of your sensor can increase the likelihood of picking up flare or ghosting, too. This is particularly noticeable if your polarizer is dirty, so make sure that it’s always clean.

Best polarizing filters to buy in 2024

Below, we’ve listed a few of the best polarized lens filters available today:

Best all-around filter

The HD nano Mk II filter is an excellent circular polarizer with outstanding build quality, toughened glass, and durable nano coatings. It offers 25% more light transmission than most circular polarizers, reducing the darkening effect by about half an f/stop. This is advantageous for DSLR optical viewfinders and for maintaining fast shutter speeds in low light. Available in various popular sizes, its performance is spectacular and worth the investment.

Best-value filter

The optical performance of the Marumi DHG Super Circular Polarizer is excellent, with no loss in image sharpness, color casts, or vignetting, thanks to its slim frame design with a thickness under 5mm. It screws smoothly into the lens filter thread, and the front element rotates easily. Available in common sizes from 37mm to 95mm, and even 105mm, the DHG Super Circular PL fits almost any lens and is well-priced, particularly in the UK.

Most versatile filter

If you’re looking for versatility, the Lee Filters LEE100 Polarizer is fantastic. This filter works with the LEE100 100mm filter system, attaching to the lens via an adapter ring and clipping to the front of the holder, allowing additional square filters to slide in behind. Its large 105mm diameter covers various lens sizes and is easy to rotate, although detaching it can be tricky. The system is costly but worth it, as Lee’s glass maintains image sharpness, reduces light by just over 1 stop, and avoids color casts. It excels in resisting fingerprints and repelling water, and comes with a high-quality zippered pouch for storage.

Best for beginners

Tiffen’s Circular Polarizer filters are a popular and affordable choice for many beginners, available in sizes ranging from 25mm to 92mm. They offer good light transmission and sharpness, with a slight cool cast that is subtle. Constructed with high-quality ColorCore Glass, these filters maintain excellent overall quality despite being slightly thicker than some competitors.

Wrapping up

From learning the answer to “What does a polarizing filter do?” to understanding when to use a polarizing filter, to hearing about some of the best options on the market, that’s most of what you need to know about working with a polarized camera lens.

Polarizing filters have remained pretty much unchanged since 1938, which means they must be great at their job. You’ll just need to spend a bit of time learning how to use a polarized lens filter. Every time you use one, you’ll need to adjust it according to the conditions, but the results will be worth it. Reduced reflections. Deeper colors. Less haze. What’s not to like?