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What is a CPL filter?

Designed to Reduce Glare & Reflection to Improve Video Quality in Your Dash Cam

Designed to reduce glare & reflection

One of the things that can ruin your dash cam’s footage is unwanted reflections. Whether it’s from your dashboard’s shiny or light-colored plastics, the sharp rays of the sun during the day, or anything where the light bounces off your view, these reflections and glares can be distracting for the driver. Worse, it can make the details like license plates, vehicle models, and road signs harder to pick up.

Thankfully, there’s a dash cam accessory that is designed to get rid of these elements, providing you with a clear view to improve the video quality – CPL filters.

What is a Circular Polarizing Lens (CPL) Filter?

A CPL (circular polarizing lens) filter is a filter that you can put over your existing dash cam lens to reduce glare and reflection. Dash cams like Thinkware, BlackVue, and VIOFO have the option to add this accessory when you purchase a compatible dash cam.

Newer dash cams like the Thinkware U3000 and the VIOFO A139 Pro - both powered by Sony STARVIS 2 - also include a free CPL filter. Alternatively, our other models come with a CPL filter included as well in our Signature Bundles . Find the perfect pre-built package for you today.

BlackVue CPL Filter


Thinkware CPL Filter

When is a CPL filter needed?

Apart from driving during hot sunny days, we also found out that CPL filters are more valuable in newer cars with a more sloped back or curved windshield. These windshields improve aerodynamics and pedestrian safety, but they produce more glare than vertical windshields. When the camera is so far back, it picks up all of the reflections from the dashboard between the lens and the windshield. Curved windshields can also cause more reflection in dash cam footage. This is because the curved surface can act like a lens, causing light to refract and reflect in different directions.

Moreover, any coating, film or dirt/debris on the windshield can lead to increased reflections on the windshield as well.

Overall, if your vehicle is prone to reflections, we definitely recommend getting a CPL filter for your dash cam. For best results, the new BlackboxMyCar Aqua Shield is also recommended to protect your lens from external environmental elements such as rain, dust, and glares. With these perfect combinations, you get glare-free, high video quality regardless if you’re using a 4K, 2K, or even full HD!

Tips on Installing a CPL Filter on Your Dash Cam

  • When installing a CPL filter, make sure there is no dust on the camera's lens or on both sides of the CPL filter. You can remove dust using a dedicated air blower or even something as simple as scotch tape.

  • Adjust the CPL filter by rotating it. We recommend parking in a sunny area and looking at the screen or WiFi app of your dash cam when you adjust it.

  • At night, you may find the CPL filter makes the video too dark. Even if your dash cam has Super Night Vision, you may want to adjust the exposure in the settings or remove the filter altogether in low-light conditions. Text

When Should I Not Use a CPL Filter?

While polarizers can improve daylight image quality, they do have a drawback: since they filter out some light, that means less light hits the camera’s sensor.

And less light means a darker image. In daylight, when ambient light is more than sufficient, that is not an issue. However, at night, this can cause the image to be noticeably darker or noisier since the sensor has to increase the ISO sensitivity to compensate for the lack of light.

You can also experience this if your car has tinted windshields, especially those with a medium dark to dark tint. Since it lessens the light sources, you may have to slide the CPL filter off of the camera if needed, especially when there aren't many light sources on the road.

Some camera brands will naturally compensate for darkened video, automatically increasing and decreasing the brightness or even disabling/enabling night vision as needed.

Thinkware CPL Filter

Lens flares, light reflections, and windshield glares can significantly impact the quality of your dash cam footage. Eliminate these issues caused from moments of extreme brightness by easily installing Thinkware’s Circular Polarizing (CPL) Filter.

Simply use the guide points located on the CPL Filter to install this on your Thinkware dash cam for enhanced color clarity, and improved light exposure.

The Thinkware CPL filter will work on lenses of other cameras, given that it covers the whole lens. This is because this CPL filter sticks directly to the lens with adhesive, and does not have a body that interacts with the camera itself. This however means the CPL filter is one-time use, and cannot be taken off without losing its stickiness. Thinkware cameras compensate for this by automatically adjusting the excellent night vision of their units, and brightness.

  • Diameter: 14.5mm
  • Eliminate Windshield Glare
  • Reduce Light Reflections
  • Correct Overexposed Footage
  • Enhance Colour Saturation and Clarity
  • One-time application with adhesive
  • Compatible with both front and rear units

Compatible with all standard vehicle models Thinkware models except the Thinkware M1)

Compatible with BlackboxMyCar Aqua Shield

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BlackVue CPL Front Filter (DR970 and DR770 Series)

The BlackVue CPL Filter is composed of high quality materials and is treated to ensure durability. In addition to the polarizer, the BF-1 includes anti-scratch hard coatings on both surfaces, as well as a UV coating.

With the BlackVue CPL Filter, you can rotate the ring to adjust the intensity of the filtering effect. This way, you can find a setting that will work best for you in all situations. Using a CPL filter at night or in a low-light environment may cause videos to appear even darker than usual, so all you need to do is slide the filter to the side (while keeping it on the dashcam).

The BlackVue CPL Filter is compatible with the following BlackVue dashcams:

  • DR970X
  • DR770X
  • DR900X Plus
  • DR900X
  • DR750X Plus
  • DR750X
  • DR900S
  • DR750S
  • DR650S

Compatible with BlackboxMyCar Aqua Shield

It is not compatible with: the DR970X Plus models, the BlackVue DR590, DR590W, DR590X, or any built-in LTE models (DR970X Plus LTE, etc)

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VIOFO CPL Filter (A229/T130/A139)

While the first VIOFO CPL filter is clipped on the dash cam, this CPL filter can be attached and adjusted by rotating the lens to best suit the camera's mounting position in the vehicle.

The VIOFO CPL Filter can:

  • protect the camera lens from fingerprints, scratches and dirt destroying
  • reduce reflections and glare from glass, metals or shiny surfaces that would damage image quality, this works in the same way as polarized sunglasses
  • Make colours more saturated and videos more beautiful
  • Be adjusted on the fly without removing the CPL
  • be used during day time and at night

This CPL filter is compatible with the following VIOFO dash cams:

Compatible with BlackboxMyCar Aqua Shield

It is not compatible with the VIOFO A119 and A129 Series, including the A119 V3/A129/A129 Plus and A129 Pro.

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VIOFO CPL Filter (A118C2/A119/A119S/A129)

The CPL filter can be used to reduce glare and improve colour production. It clips over the lens housing and the lens can be rotated in the housing to adjust the amount of polarization as needed without removing the CPL.

This CPL filter is compatible with the following VIOFO dash cams:

Compatible with BlackboxMyCar Aqua Shield

It is not compatible with the VIOFO A129 IR rear camera.

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