CPL vs non-CPL Lens filter, Panorama 2 / S ( Circular Polarized Filter ) v1.12.06

niko

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So, I decided to do some side by side test in different daylight on two Panorama-series dashcams. One is Panorama 2, other is Panorama S that can use CPL lens filter.

Why CPL filter needed ?
In dashcams it's mostly needed for daytime driving ( especially in sunny day ) in order to remove dashboard and A-pillars glare. For more info about CPL filter technology in photography world you may read HERE and HERE.

One of the advantages of CPL filter in regular everyday photography or video-shooting is to improve image by bringing more natural colours and reducing glare, but not always this rule will apply to dashcam-world ( as you will see from my tests below ). In dashcams it's all depends on how correctly default colour palette is set by the factory. Dashcam main purpose is not to provide 100% correct colours, but to record vital details from every day- and night driving ( or when car is parked ) and colour settings are not always set to the most correct ones. They are set to be somewhere in balance between day and night mode. Thats why you see on Panorama 2 / S colours being at day time too strong ( too contrast ), but this has been done in order to compensate colour palette reproduction at night, because if at the first place ( at day time ) colours would be set to be correct, then at night driving those colours would look dull. With use of CPL filter I could see that picture kinda brightened up a little bit ( in some places maybe too bright ), but at the same time glare was removed.
So, this was just sort of "intro" why CPL filter purpose can not be taken on dashcams same way as on everyday photo-video cameras.
Main purpose of CPL filter on dashcams is to reduce glare in order to record more outside details, especially those which are situated in the area of windshield dashboard reflection.

Just few small notes:

- CPL filter will remove only this glare which is caused by directly shining sun. It will not remove completely glare if sun is from rear or sides, as you may see from my tests.

- If your car A-pillars are light colour ( like on my car ), then it is very hard ( almost not possible ) to remove that A-pillar glare, so this is normal. White surface glare is always much harder to remove than from black surface.

- If your car dashboard is black colour, but dusty, - dust will create more glare.

- If your car dashboard is black colour, with no dust, but nicely polished with auto-care shine, - this still will create glare.

... so the best possible to minimize dashboard glare is to have kinda dull-colour dashboard. Its not that I am making a propaganda here, - myself I like when my car plastics / trims / dashboard is clean and shining, I am just providing facts that causing glare on dashboard.


..........................................................................


Tests were done on two different days. First day was slightly cloudy and on the second day weather here in Ireland made a good surprise by giving a nice sunny day where I could test CPL filter capabilities.

On both days I was using same Firmware v1.12.06, but on Day 1 ( 20 April '14 ) I used 12Mpbs bit-rate and on Day2 ( 21 April '14 ) was using the highes 21Mbps bit-rate on both dashcams.

I have also made tons of screenshots from different scenes just to show you what are the differences of same dashcam without CPL filter vs dashcam ith CPL filter.


Below is two Panoramas mounted for side by side test.


CPL1 (2).jpg


Day1 Side by side

Top: No CPL
Bottom: With CPL

P.S. - on Panorama S ( with CPL filter ) I forgot to set correct time, so dont pay attention on it.



Individual videos from Day1




You may download raw / original files from HERE.


Screenshots


20 April CPL vs No CPL v1.12 (1).jpg


20 April CPL vs No CPL v1.12 (2).jpg


20 April CPL vs No CPL v1.12 (3).jpg


20 April CPL vs No CPL v1.12 (4).jpg


20 April CPL vs No CPL v1.12 (4).jpg
 
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Day2 Side by side

Comparison.jpg


Top: No CPL
Bottom: With CPL

P.S. - on Panorama S ( with CPL filter ) I forgot to set correct time, so dont pay attention on it.


Individual videos




Original / raw video files you may download from HERE



Screenshots


21 April CPL vs No CPL v1.12 (1).jpg


21 April CPL vs No CPL v1.12 (2).jpg


21 April CPL vs No CPL v1.12 (3).jpg


21 April CPL vs No CPL v1.12 (4).jpg


21 April CPL vs No CPL v1.12 (5).jpg


21 April CPL vs No CPL v1.12 (6).jpg


21 April CPL vs No CPL v1.12 (7).jpg
 
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21 April CPL vs No CPL v1.12 (8).jpg


21 April CPL vs No CPL v1.12 (9).jpg


21 April CPL vs No CPL v1.12 (10).jpg


21 April CPL vs No CPL v1.12 (11).jpg


21 April CPL vs No CPL v1.12 (12).jpg


21 April CPL vs No CPL v1.12 (13).jpg


21 April CPL vs No CPL v1.12 (14).jpg


21 April CPL vs No CPL v1.12 (15).jpg
 
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21 April CPL vs No CPL v1.12 (24).jpg



21 April CPL vs No CPL v1.12 (25).jpg



21 April CPL vs No CPL v1.12 (26).jpg



21 April CPL vs No CPL v1.12 (27).jpg



21 April CPL vs No CPL v1.12 (28).jpg



21 April CPL vs No CPL v1.12 (29).jpg



21 April CPL vs No CPL v1.12 (30).jpg



21 April CPL vs No CPL v1.12 (31).jpg
 
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Nice CPL write-up!

Maybe you can do the slow SPIN test like I did on my old 0801 DIY (perhaps place a white piece of paper on your dash)
http://dashcamtalk.com/forum/thread...reduce-windshield-dashboard-reflections.2343/
(there are also more reflective side by side snap shots, the open garage one is good)


Spin test done in my video from Post 2.
I did not had white paper on dash, but still result can be clearly seen.
Next time I will wipe off dust from my dashboard, didnt had time back them, was too busy ;)


 
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What settings do you have on your panorama to acheive such sharp results? Mine doesn't seem to be that way.
 
What settings do you have on your panorama to acheive such sharp results? Mine doesn't seem to be that way.

Pano does not give any options to play around with image "modification", - everything is default.
I clean lenses with special lens cleaning liquid, - this may play a role in image differences if lens are not properly cleaned. Only wiping with cloth is not enough.
 
I had a customer ask how they can tell if the CPL is rotated to the correct position. My tip is to place a piece of white paper on your dashboard. This high contract reflection will clearly show up even on the tiny screen so you can spin the CPL until the reflection is reduced as much as possible.
 
I had a customer ask how they can tell if the CPL is rotated to the correct position. My tip is to place a piece of white paper on your dashboard. This high contract reflection will clearly show up even on the tiny screen so you can spin the CPL until the reflection is reduced as much as possible.

I check mine, by watching a portion of the sky darken. With the darkest setting, being polarized. It helps that it's usually blue.
 
The way I understand CPL to work, it is dependent on the angle of the incoming light, hence dependent on the angle of the sun in the sky, and the reflecting surface. Which is why a CPL filter is completely rotatable. So unless you intend to find the correct rotation setting of the filter every time you are in the car, it sure sounds gimmicky to me to have one.
 
The way I understand CPL to work, it is dependent on the angle of the incoming light, hence dependent on the angle of the sun in the sky, and the reflecting surface. Which is why a CPL filter is completely rotatable. So unless you intend to find the correct rotation setting of the filter every time you are in the car, it sure sounds gimmicky to me to have one.

it does work. but like a lot of things it is not perfect. Some love them, others don't . . .

As I normally only drive in the daytime. Mine was setup correctly first time I installed it & has remained untouched since. It does affect night and/or low-light movies, if it's on, making them dimmer.
 
apologies, I am not saying that it has no effect, and I can understand why I came across that way. A little bit of that photography enthusiast in me keeps bugging me that one should always find the best CPL setting at every shot...
 
The way I understand CPL to work, it is dependent on the angle of the incoming light, hence dependent on the angle of the sun in the sky, and the reflecting surface. Which is why a CPL filter is completely rotatable. So unless you intend to find the correct rotation setting of the filter every time you are in the car, it sure sounds gimmicky to me to have one.

I agree.
Similar thing I have mentioned in my Post 1. It's all about angle of incoming light.

... - CPL filter will remove only this glare which is caused by directly shining sun. It will not remove completely glare if sun is from rear or sides,
 
I definitely need a camera with a CPL filter at some point as I have the same dash as Niko and that speaker grille reflection causes problems with every Ambarella A7 camera I've tried yet - the Novatek ones don't like it but seem to handle numberplates through the grille better!
 
Nice!! I'm assuming this is compatible with the Panorama G as well?
 
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