VIOFO CPL Filter Circular Polarizer for A129 Duo / Plus / IR / A119 V3 / mini 2 Dash Camera Lenses

When I first got this filter, having looked up multiple videos and posts online about how to adjust it if it was not adjusted properly, the first thing I did was do what all those videos said to do. I held it against my mobile phone screen which was displaying an image of protractor, on which was highlighted a red line at a 45⁰ angle. I twisted the filter so that at 45° from it's horizontal fitting position it was supposed to completely cut out the light from the phone screen.Three things then:1. It does not cut out the light at 45⁰.2. It does not cut out the light completely as shown on video in any circumstance.3. It only cuts out the light to the maximum extent that it can when twisted to 0⁰ (vertical) and not at 45⁰.Point 2 may be because of video photography, lighting and metering on whatever was used to record the videos.Anyway, I initially thought that the filter wasn't aligned properly, but before man-handling the lens in order to turn it I tried something else which made more sense.I sat in my car holding the lens in the proper orientation, long slit up, front facing windscreen and at the same angle as the lens was set on the dashcam (basically vertical and horizontal to the windscreen). I was holding it at a distance from my eyes where I could see the reflections on the windscreen of the side pillars, speaker grilles and vents on my dashboard. It was not a bright day but they were visible on the windscreen. Whilst looking through the filter they disappeared. Twisting the filter to the left and right I saw the reflections coming back into view. At no point other than at the level proper position for fitting did I see an improvement in how it reduced reflections.So obviously the only assumption I could make from this is that it arrives pre-set and in it's correct orientation. In my opinion blindly following the instructions online is a mistake because when mine was turned 45⁰ I could see all the reflections.The videos online are all dated from and around 3 years ago. Maybe something has changed since then, I don't know, but physically looking through it in the orientation that it is intended to be utilised, the pillars, speaker grille and vents all vanished.It was a dull day so there weren't really strong reflections from the dash itself but my pillars are light cream, and they weren't visible any more.So in the end I put the CPL on the dashcam without forcing an adjustment to make it block out the maximum amount of light it can at 45⁰ as the videos all indicate is correct, and I left it at it's preset 0⁰.I do not really know why adjusting it like they do on youtube is necessary but I suggest you do the same as I did before blindly trying to adjust to a chart on a screen. Sit in the car and look through it. I think Viofo are reputable enough to make sure that the manufacturers adjust these properly before supplying them.While I was looking through it during the test, though It certainly added definition to the scene it also definitely lowered the light passing through it, as it obviously would. Please see the oictures I've uploaded and look at the vents reflections vanish.I used to take photographs a lot, back in the days of film and more recently with digital autofocus SLR cameras. Regardless whether it was a linear or circular polarizing filter, I used to adjust exposure up slightly when using one. I did the same with the A119, adjusting it +⅓, further testing will see if I need to adjust it one stop higher or even back to 0, depending on how the sensor copes with the reduction. In a perfect world it will adjust itself but I need a bright day to do those tests.As for cost, it is expensive for what it is. But that being the fact should also mean that it arrives configured to immediately be used from the box, with no adjustment. I think reducing the glare, especially on sunny days is worth it.

The polarising filter is almost a must have to cut down reflections and glare. It improves day time videos enormously but does detract from night time images slightly but really is swings and roundabouts as some parts of images are still improved. So important in day time it would be nice if Viofo included along with the Dash Cam. It does seem high quality and clips on firmly to the camera lens. Recommend you purchase this for your Viofo Dash Cam.

Fitted perfectly to an Aukey DR02. Works exactly as intended.Not sure what all the other reviews are saying about adjustment, this is a CIRCULAR polarising filer, so cannot be adjusted, though the box says it is set at the factory.

Easy to fit to dash cam, I have A119s V2 and makes a difference in terms of reducing reflections.The only down side was mine didn't seem to be aligned properly when I received it, so I had to rotate it and test it before I found the correct orientation. It's not difficult to do and there are videos online showing you how to do it, it just takes a few mins to do as I found it better to take the card out and test the footage on a larger screen to make sure. However, it is well worth doing as it does reduce reflections quite a bit.A polariser does reduce the amount of light entering the dash cam, so is not ideal for night time, but I have not removed mine for night time, as yet and still found the footage on my dash cam to be fine so far. The beauty of this polariser is that it can be unclipped quite easily, if you wish to do so and I may do it when we get back into winter when most of my driving will be in the dark again.

Using this has made a way bigger difference than I expected when looking at the footage from my dashcam. Highly recommend.

Filters out most dashboard reflections on sunny days and does its job well but a bit pricey for a piece of plastic, should be 5 quid!When buying a viofo dash cam it should be included in the box as mandatory like all the sticky pads and trim tool etc that are included

Fitted these filters on my VIOFO dashcam to get rid of windscreen reflection and sun reflecting on road surfaces after rain. Not very impressed. Simple polaroid glasses had way more effect. Keeping them only as protection for the cam lenses, but .... way too expensive just for that!

Brought these for my Dashcam as it kept getting glare on the windscreen which you could see on the video footage. 90% reduced glare. Very happy with this and easy to fit.