Polarizing Filter on Dashcams

[Al Drake]

I did some googling and this got in to my eye.
Just out of interest i ordered one, if nothing else this item has good factory made (metal?) rings.
Of course, price is low so i keep my expectations low too.
http://dx.com/p/external-clip-0n-polari ... ack-163738

Did you get it for an iPhone? If so then it might give some desired results. At that price you can't go wrong. I think I ordered something from that site and it took a while to arrive but I was satisfied with my purchase.

 

[Sabe]

I did some googling and this got in to my eye.
Just out of interest i ordered one, if nothing else this item has good factory made (metal?) rings.
Of course, price is low so i keep my expectations low too.
http://dx.com/p/external-clip-0n-polari ... ack-163738

Did you get it for an iPhone? If so then it might give some desired results. At that price you can't go wrong. I think I ordered something from that site and it took a while to arrive but I was satisfied with my purchase.

Not for iPhone, i will cut the back part off and use it with my gs1000.
At best i will have it in three weeks, at worst in two months :lol:
There might be some problem to get it close enough to lens, but time will tell.

 

[Al Drake]

I did some googling and this got in to my eye.
Just out of interest i ordered one, if nothing else this item has good factory made (metal?) rings.
Of course, price is low so i keep my expectations low too.
http://dx.com/p/external-clip-0n-polari ... ack-163738

Did you get it for an iPhone? If so then it might give some desired results. At that price you can't go wrong. I think I ordered something from that site and it took a while to arrive but I was satisfied with my purchase.

Not for iPhone, i will cut the back part off and use it with my gs1000.
At best i will have it in three weeks, at worst in two months :lol:
There might be some problem to get it close enough to lens, but time will tell.

That might work. Good luck.

 

[Sabe]

Now i have cpl filter installed and next follows some testing.
Filter is 25mm Marumi CPL, other sizes may fit too but this was quite easy to install.
I don't like that new google image service, it messes up images.

 

[javr]

I thought I must get a filter, which will fit a 33,6mm diameter of that black "gear-wheel" signed as "f=3.2 F2.0 WIDE ANGLE LENS".
I tried to unscrew it, and pulled it off - no luck. Just heard some cracks and rather left it alone. And the camera wasn't so cheap to use the usual method ("accidentally" drop it to the concrete floor). So how did you get it off ?

 

[Sabe]

You must open camera, the remove those four very small screws.

 

[mollydog]

I just got my self the Gizmon polariser from Amazon for £25

http://www.amazon.co.uk/gp/product/B007 ... UTF8&psc=1

I'm going to give it a go on the Blackvue DR500

 

[Al Drake]

Now i have cpl filter installed and next follows some testing.
Filter is 25mm Marumi CPL, other sizes may fit too but this was quite easy to install.
I don't like that new google image service, it messes up images.

That brand got good reviews on Amazon. Good luck

 

[p_dashcam]

That was interesting, i tested polarized sunglasses on two identical gs1000 camera at the same time so they were exactly at the same position side by side.
Result was very poor with sunglasses on, no matter how i set ev value it was always wrong, if sky was ok then road was too dark, and if road was ok then sky is burned out.
It is amazing how good camera actually is without any filter.
Next week some time i will have my cpl filter, sunglasses i will forget from now on.

Left image below is without any filter and right is with sunglasses.
https://lh6.googleusercontent.com/-TWQQ ... mage01.jpg
https://lh6.googleusercontent.com/-DbXN ... mage02.jpg
https://lh4.googleusercontent.com/-SltX ... Image5.jpg
https://lh5.googleusercontent.com/-9Pgw ... Image6.jpg
https://lh3.googleusercontent.com/-nebF ... Image7.jpg

I really hope u faced the sunglasses lens "inside out".... thats what i did with cinema 3d polarised glasses, and angled them 90 degrees, worked perfectly and stopped 90% of reflections on windscreen apart from on the sides.. with slight vignetting as the lens is not that big to cover the space infront of the gs9000. But minor as only happens in top left corner/

 

[RSole]

I haven't read all the posts, but has anyone mentioned that some 3D movie glasses are circularly polarized, whereas sunglasses are linearly polarized. I thought that the movie glasses would not work that well.

 

[Sabe]

I haven't read all the posts, but has anyone mentioned that some 3D movie glasses are circularly polarized, whereas sunglasses are linearly polarized. I thought that the movie glasses would not work that well.

Movie 3D glasses can be circular or linear, but based on experience they do not work as desired because of cheap material.
Like me you can do tests with them, but you will end up buying the real thing made of glass

 

[AgentSmith007]

I haven't read all the posts, but has anyone mentioned that some 3D movie glasses are circularly polarized, whereas sunglasses are linearly polarized. I thought that the movie glasses would not work that well.

Look at my post here viewtopic.php?p=7701#p7701
and download video file http://home.comcast.net/~mozartguy/cpl.zip

 

[xreyuk]

Anyone figured out a way to make this removable?

I've got one on my F520 but the night video, as everyone says, is very dark. I need to have one however, because where I have my dashcam, the reflections take up a LOT of the picture.

 

[mollydog]

I too ordered one of these Gizmon polariser from Amazon for £25

on taking a look on the back of the cpl I noticed the aperture was rather small and more than likely as it was made for the iphone/ipad it would vignette on the BlackVue DR500

but once I took a better look I noticed the cpl itself had more or less the same size aperture/diameter so thought I'd make the hole bigger and see how I got on

as it wasn't a good fit round the barrel I heated up the plastic and made it a bit more round

sad to say it looks a too much home made

all's not lost, my BlackVue came with a lens cap sort of thing that will make a good holder for the cpl and if I get time this week, I'll make a hole in the middle and supper glue the thread bit of the plastic of the cpl holder to the lens cap

I hope this is of use to some of you and may give you ideas how to fix it to your DVR camera

 

[V8Rocks]

Why, not just use dual sided 3M tape?

I would file off thread on the filter housing ring, so it is flush and flat, then just cut out 3M tape to cover new flat surface we just created and mount it to the camera lens or body.

Actually, I would first use the tread portion to cut out inside circle on the 3M tape by pressing it against it (the thread edge looks pretty sharp). Once thread is flattened/removed, just attach tape and cut external tape excess following the outer contour of the filter ring.

It should be neat. I will give it a shot. Reflections from dash are annoying. Not like I ever watch the recordings. Hopefully never need to watch it

 

[mollydog]

Thank you for mentioning dual sided tape, I'm going to be honest and say I never thought of that and that sounds like a very good idea and for sure will make it look a lot more a finished item and not a home made thing, hopefully I'll get some time this weekend to do this and will show the results

 

[Sabe]

Thank you for mentioning dual sided tape, I'm going to be honest and say I never thought of that and that sounds like a very good idea and for sure will make it look a lot more a finished item and not a home made thing, hopefully I'll get some time this weekend to do this and will show the results

I don't know the structure of your lens, but most important thing is that it should be easily detachable for night driving.

 

[Mitch]

I have an old pair of oakley with great optical polarized and UV lens. I am thinking of cutting a large piece and putting this to work with the DVR for daytime driving. There is a need to have a flipping mechanism for nightime driving. I am still exploring the options.

 

[Sabe]

Here some notes of CPL filter.
My dvr is GS1000 and i found out that there is two sizes that are easiest to install, 25mm and 30,5mm.
I used cheap (16 eur) Marumi CPL filter because it has those sizes available.
Soon i noticed that CPL filter is must have accessorie with dvr, it removes all glare that comes from your dashboard to windshield.

However, experience taught me that cheap cpl filter is not flawless, these cheap filters give nasty reflection when sun hits it from the side, that is because it's made of cheaper materials and it's not intended to work in direct sunshine.
Then next thing to do is make some kind of lens hood or install camera deeper inside your car so sun don't hit it directly.
Other possibility is buy more expensive filter which work better in the sunlight (maybe 80+$) but then you probably can't have small filters sizes, i'm guessing that smallest reflection free filter is maybe 42mm or so.
All of these filters are made of two sides of glass and one or more plastic film is pressed between them.
It means that you can't cut filter to smaller bits, because if you do then air will go inside layers and destroys it in X amount of time.
My advice is.
-Use cpl filter.
-Shade it or install dvr deeper in the car out of direct sunlight.
-Buy expensive reflection free cpl filter and step up rings to make it fit.
These filters are made of glass, if you take good care of it it will last the rest of your life, so in that perspective price is not so very important factor.

Here you can download sample images of dashboard glare on/off, and tube video.
https://mega.co.nz/#!xwcESTTR!a7jvHz_dz ... FChCf1479k
http://youtu.be/UP21F7OT7rg

 

[colingbradley]

Just did a quick check on eBay and found CPL filters (Circular Polarizing I think) going really cheap.

Fix the filter in place and then rotate it so you get the best effect in the same way as on a camera.
Mark that position and do the same for the neutral position.

At night, you rotate it to the neutral position and when the sun is high or directly affecting the image, rotate it to the 'best' position.

The only real limitation is the size and how you would mount it.

I am considering some black faux velvet for the dashboard as even though it is black, it does reflect a lot.
The other thing I will be making is a small hood for the top and bottom (see what it looks like for a 180 wide angle camera lens).
The material for the hood should be mat black and light weight, good quality thin card will be perfect.

Anyone done these things?
(Very odd, after I posted this, up popped a detailed example of fitting a CPL....)
This is my first dashcam:
BlackVue DR400G-HD V2

So far so good, but I will be needing help from you guys to see if it is possible to solve the fixing problems I am having!