Why Your Dashcam Needs a CPL Filter (And How to Use It Properly)
The Problem Every Dashcam Owner Faces
Ever noticed how your dashcam footage gets ruined by:
Annoying windshield reflections
Washed-out colors during daytime
Glare from other cars’ headlights at night
Sunlight making license plates unreadable?
These aren’t just minor annoyances – they can completely ruin crucial evidence when you need it most. That’s where a CPL (Circular Polarizing Lens) filter comes in as an essential dashcam upgrade.
What Exactly Is a CPL Filter?
A CPL is a special rotating lens that attaches to your dashcam to:
✔ Block reflected light waves (eliminating glare)
✔ Reduce windshield reflections
✔ Enhance color saturation
✔ Improve contrast in bright conditions
Think of it like polarized sunglasses for your dashcam – it filters out scattered light that would otherwise degrade your video quality.
5 Situations Where a CPL Saves Your Footage
1. Dashboard Reflection Elimination
That ghostly reflection of your dashboard? Gone. CPL filters remove up to 90% of interior reflections that plague standard dashcam footage.
2. License Plate Visibility
Direct sunlight often turns plates into bright white rectangles. A properly adjusted CPL maintains plate readability in challenging lighting.
3. Rainy Day Clarity
Wet roads create blinding glare. CPL filters cut through this for clearer accident documentation.
4. Night Driving Improvement
While primarily for daytime, some CPL filters (like VIOFO’s) still help reduce oncoming headlight glare at night.
5. Color Accuracy
Get truer-to-life colors by removing the “haze” caused by scattered light pollution.
How to Install and Adjust Your CPL Filter
Installation Steps:
Clean your dashcam lens thoroughly
Align the filter’s mounting threads
Screw on gently (don’t cross-thread)
Rotate to find the optimal position
Finding the Sweet Spot:
Park facing a reflective surface (another car’s windshield works well)
Slowly rotate the filter while watching the live view
Stop when reflections disappear
Tighten slightly to lock position
Pro Tip: Recheck adjustment seasonally – the sun’s angle changes throughout the year.
CPL Limitations to Know About
While incredibly useful, CPL filters:
Reduce overall light intake slightly (about 1-1.5 stops)
Work best when properly aligned
May need removal in extremely low-light conditions
Don’t eliminate all reflections (but dramatically reduce them)
VIOFO’s CPL Filter Advantage
VIOFO’s specially designed CPL filters:
Maintain night performance better than generic filters
Feature precision threading for perfect fit
Include anti-reflective coatings
Are optimized for their specific camera models
FAQ
Q: Should I leave the CPL on all the time?
A: Yes for most situations, but consider removing it for very dark country roads.
Q: Will it work with my tinted windshield?
A: Yes, though you may need more adjustment to find the sweet spot.
Q: How often should I clean it?
A: Weekly with a microfiber cloth to maintain performance.
Q: Can I use one CPL for multiple dashcams?
A: No – they’re model-specific for perfect alignment.
The Bottom Line
A quality CPL filter is one of the most cost-effective ways to dramatically improve your dashcam’s video quality. For about the price of a coffee, you can:
Eliminate frustrating reflections
Capture clearer license plates
Get more usable footage in challenging conditions
Enhance your evidence quality
How to choose a suitable CPL?
When choosing a CPL, ensure the size and model match your dash cam lens. Opt for a well-known brand and a high-quality CPL, as inferior products may negatively affect video quality.
For instance, VIOFO has customized CPLs for each dashcam model by adding an antireflection film to improve image quality. Here are some specific CPLs for various VIOFO models:
CPL-100 Filter is designed for front & rear cam of A119V2/A119V3/A119MINI2/A129 DUO/A129 PRO DUO/A129 PLUS DUO
CPL-200 Filter is designed for front cam of A229/T130/A139/A139 PRO/WM1
CPL-300 Filter is designed for rear cam of A229/A229 PLUS/A229 PRO/A139/A139 PRO/T130
CPL-400 Filter is only designed for the VS1
