Street Guardian SGGCX2pro CPL Filter thoughts?

Dawsy

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Been driving around with the CPL filter on for couple days, and i'm now just checking out some footage, And i noticed an odd rainbow glare on the bottom left corner of my dash cam.

Has anyone else had the same issue with the filter? Or maybe even just the camera in general?
 

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I think this is a common problem with cars that have certain kinds of sun protection build into the glass or maybe aftermarket, it is a issue that have surfaced in here from time to time.
I dont think it have anything to do with the CPL filter or the camera,,,,, other then being a cog in a unfortunate setup.
 
I think this is a common problem with cars that have certain kinds of sun protection build into the glass or maybe aftermarket, it is a issue that have surfaced in here from time to time.
I dont think it have anything to do with the CPL filter or the camera,,,,, other then being a cog in a unfortunate setup.
I'll give my window a good clean & dashboard tomorrow. The glare is where my 'P' plate used to be, maybe that is causing the glare?
 
I think your best option as it is probably a coating on your windscreen is to drop the CPl filter and get a black dashmat that will reflect less in the windscreen.
In my car i use both CPL filters and a dashmat ( home made as no one make a dashmat for my obscure little Suzuki car ) i am also wanting to get new A pillar plastic trim and paint it flat black, but have not gotten around to that yet.
 
I've not seen the colours on the dashboard as well as the glass like that before!

As Kamkar says, it is caused by the tint on your windscreen, not a fault of the camera or filter.

I notice that the CPL is not actually working to remove the reflections, so unless you can fix that then it is not worth having anyay...

The glare is where my 'P' plate used to be, maybe that is causing the glare?
I don't know what a 'P' plate is, but if it was stuck to the windscreen tint with adhesive then it is possible the tint got stressed when the 'P' plate was pulled off, the coloured patterns are stress patterns within the tint.
 
I've seen that type of artifact in some car windows when wearing my polarized sunglasses. It has to be specific to select vehicles because I don't see it all that much.
 
I don't know what a 'P' plate is, but if it was stuck to the windscreen tint with adhesive then it is possible the tint got stressed when the 'P' plate was pulled off, the coloured patterns are stress patterns within the tint.

It is a square plate with a "P" - to indicate provisional licence holder. We use these in Australia to show other road users that you haven’t got your full licence yet and are still subject to certain licence conditions but are not a learner driver, who, consequently will have a "L" plate.

Picture: https://www.approveddrivingschool.com.au/wp-content/uploads/2017/07/l-plate-p-plate3.png
 
Been driving around with the CPL filter on for couple days, and i'm now just checking out some footage, And i noticed an odd rainbow glare on the bottom left corner of my dash cam.

Has anyone else had the same issue with the filter? Or maybe even just the camera in general?

The rainbow effect you are seeing in your video is called "Birefringence" which is a double refraction caused by the polarization from the CPL combined with the polarization from tint on your windshield and can also be caused by stress patterns in the glass. So, in effect it is a phenomenon in physics where polarized light is being polarized again. It’s essentially like having two polarized filters, each aligned perpendicular to one another. Sometimes this effect is seen on side and rear car windows made of tempered glass when wearing polarized sunglasses and is caused by the tempering process when the glass was manufactured. Front windshields are made from laminated glass and generally don't exhibit this problem the same way. If you remove the CPL the rainbow effect will disappear.

This article, "Why You're Seeing Rainbows in Car Windows" offers a good explanation of the phenomenon.
 
I'll give my window a good clean & dashboard tomorrow. The glare is where my 'P' plate used to be, maybe that is causing the glare?

Although the strongest rainbow effect you are seeing in your image is on the lower left corner it is not likely caused by your 'P' plate. Notice that you also have a more subtle but similar rainbow refraction on the upper right corner of the image and down the side of the glass.

This appears to confirm birefringence as the problem.

refractions.jpg
 
The rainbow effect you are seeing in your video is called "Birefringence" which is a double refraction caused by the polarization from the CPL combined with the polarization from tint on your windshield and can also be caused by stress patterns in the glass. So, in effect it is a phenomenon in physics where polarized light is being polarized again. It’s essentially like having two polarized filters, each aligned perpendicular to one another. Sometimes this effect is seen on side and rear car windows made of tempered glass when wearing polarized sunglasses and is caused by the tempering process when the glass was manufactured. Front windshields are made from laminated glass and generally don't exhibit this problem the same way. If you remove the CPL the rainbow effect will disappear.

This article, "Why You're Seeing Rainbows in Car Windows" offers a good explanation of the phenomenon.
I'll try it without the filter, and get back to you. :)
 
So argh i feel like an idiot haha, I still have the plastics on my CPL filter... *walk of shame* Thought i removed them prior :p
 
So argh i feel like an idiot haha, I still have the plastics on my CPL filter... *walk of shame* Thought i removed them prior :p
Take solace in the fact that you're neither the first nor will you be the last person to do that. ;)
 
Interestingly, the protective plastic film on the CPL can actually introduce the same double refraction effect. I'm still interested to know if the rainbow problem went away completely. Hope it has.

Anyway, as @DT MI mentioned something like this happens to all of us sooner or later. With me it's often been discovering that I've left a lens cap on dash cams that have them.

As a special honor I think it's time to roll this old image out just for you! :smuggrin:

Dohcam.jpg
 
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Interestingly, the protective plastic film on the CPL can actually introduce the same double refraction effect. I'm still interested to know if the rainbow problem went away completely. Hope it has.

Anyway, as @DT MI mentioned something like this happens to all of us sooner or later. With me it's often been discovering that I've left a lens cap on dash cams that have them.

As a special honor I think it's time to roll this old image out just for you! :smuggrin:

View attachment 49346
The rainbow seems to have gone away since i took the plastics off the CPL filter :) I also moved the camera bit more onto my side so i can press the emergency button easier & gave my window a bit of a clean.

Lesson learnt, always triple check things.
 

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