Putting a CPL filter on the SG9665GC

[kamkar]

So i was a little bored yesterday evening, so to pass time i found the little CPL filter supplied with the 0806.
First i was making a little bracket of some plastic tube i planned on gluing on the SG9665GC, but that do not work as the lens of the dashcam is so close to the windscreen.
So i enden up with taking the glass out of the 0806 CPL filter, and that alone did work but have to be used with the tall of the 2 mount brackets supplied with the SG9665GC, the reason for this is the glass from the CPL filter is "large" in diameter so on the low bracket its a extremely tight fit.

For testing i just used 2 sided tape to glue the CPL filter onto the SG9665GC, but doing that i have no means of ajusting the CPL filter by turning witch seem to be the norm.
So in desperation i held up the CPL and looked thru it at my LCD tv, and then turnes the CPL untill it got dark, i then assumed this was the "this side up" mark and i glued it onto the dashcam that way.

But today i found out that assumption is the mother of all farwkups cuz in my footage there is still reflections in my windscreen
So for my drive tomorrow to aid my friend i have planned to pry the filter off the dashcam while in place and then try to rotate it in front of the lens to find the sweet spot, and then press it back on the 2 sided tape.

I can not do more with this at the moment as my cam is still only test mounted in my car, but when i get it in its permanent place i will use the tall mounting bracket and make sure i have enuff clerance between dashcam and windscreen to proceed with my CPL experiments.

So to sum it all up.
It can be done, but you have to use the tall mounting bracked, and maybe even make that even taller to make room for CPL filter.

The 0806 CPL filter is not tall, around 4 mm i think, but as is there is no room for it at least not using the low mounting bracket i use ATM.

 

[niko]

I tested 2 month ago cpl filter from 0806. Even if using a paper-thin double-sided tape, image will have round shades in corners because of mini 0806 cpl filter lens are too small in diameter and "ring-frame" that holds lens is too thick for that application. I am working on some other more practical solution.

 

[kamkar]

That was allso what i was fearing using the complete 0806 CPL and the pice of tube i first experimented with.

Anyway i will keep experimenting as i know many ppl are bothered with reflections, personally i can deal with the reflections i have.

BUT it is allways nice to be able to help other folkes, and it is nice to keep ones hands and brain busy

 

[Nigel]

You are probably exactly 90 degrees out with it the correct way around if your TV went completely black.

Don't forget that as well as having the correct angle, you need to also have the front at the front. If you mount it with the filters back at the front then it will not block reflections - if you have forgotten which is the front and which is the back then hold it up to a mirror, if you can see the reflection of your eye then it is the correct way around, if the reflection of your eye is blocked then you are looking at the front.

 

[kamkar]

Yeah Nigel i have come to the same conclusion, i am doubtfull my experiement tomorrow will work, so THX for telling me how i can figure it out.

 

[Street Guardian USA]

It looks like it should fit, might want to move the stick tape to the extreme outside edges though, one side looks too close to the lens. If not this filter I'm sure we can find something. And you're right probably best to use the thicker of the two mounts.

I tested 2 month ago cpl filter from 0806. Even if using a paper-thin double-sided tape, image will have round shades in corners because of mini 0806 cpl filter lens are too small in diameter and "ring-frame" that holds lens is too thick for that application. I am working on some other more practical solution.

"vignetting" is the word you want
http://en.wikipedia.org/wiki/Vignetting

 

[DT MI]

...And you're right probably best to use the thicker of the two mounts....

A couple of other options to gain more clearance would be either 1) an additional piece of VHB tape (doubling the thickness) or 2) a small piece of plastic/plexi-glass affixed to the glass with VHB tape and then the camera mounting plate attached to that. Either should provide enough clearance.

I would probably use the second method as it seems to me it would be a bit more solid.

 

[niko]

It looks like it should fit, might want to move the stick tape to the extreme outside edges though, one side looks too close to the lens. If not this filter I'm sure we can find something. And you're right probably best to use the thicker of the two mounts.



"vignetting" is the word you want
http://en.wikipedia.org/wiki/Vignetting

yeah, vignetting is the word that I never remember.

 

[ddnut]

You are probably exactly 90 degrees out with it the correct way around if your TV went completely black.

Interesting. I grabbed my polarized sunglasses to do a quick test with the SG9665GC and accidentally discovered that my LCD computer monitor went dark. But in my case the orientations both matched. Due to the annoying reflections that I see when driving, I was planning to add polarization to my next pair of eyeglasses. So now I wonder if there is a default orientation they use for eye wear or it I would have a 50/50 chance of it working.

BTW, I received my dash mat today and will find out tomorrow how well it works to reduce reflections.

 

[Nigel]

Interesting. I grabbed my polarized sunglasses to do a quick test with the SG9665GC and accidentally discovered that my LCD computer monitor went dark. But in my case the orientations both matched. Due to the annoying reflections that I see when driving, I was planning to add polarization to my next pair of eyeglasses. So now I wonder if there is a default orientation they use for eye wear or it I would have a 50/50 chance of it working.

BTW, I received my dash mat today and will find out tomorrow how well it works to reduce reflections.

I thought polarised sunglasses where sold for driving so they should be vertically polarised!
But maybe the people who design them these days have forgotten the original research?

I guess your monitor may be polarised horizontally, I can't think of any reason that it should be vertical other than to reduce reflections off the desk... actually, when setting the angle of the CPL on the dashcam I use my hand on the dash to provide a bright reflection, when using my keyboard my hands are also just below the screen, maybe a horizontally polarised LCD would be bad!

If you have a decent polariser filter with a white mark to show vertical which can be trusted to be in the correct place (not a mini 0806 one!) then you could easily test your glasses to see if the polarisation is vertical? Alternatively test them in car to see if they block reflections...

 

[kamkar]

I found out i did do right, or so it seemed.
BUT ! i had to flip the CPL 180 degrees yesterday, and i was never able to make all the reflections in my windscreen go avay, and i did play around with the damm thing for a good 30 - 45 minutes.

Just looked thru CPL at reflections in my windscreen, 1 way could block some and the other way i first had it was no good.
I assume i must have flipped the CPL before i put it on the dashcam at home.

On the SG9665GC its hard to see on the little screen when you have hit the sweet spot, so yesterday i was running in and out of my friends place to chek progress on computer screen.

 

[alexsoll]

very interesting topic, if anyone will do beautifully, that would be fantastic

 

[ddnut]

I thought polarised sunglasses where sold for driving so they should be vertically polarised!
But maybe the people who design them these days have forgotten the original research?

I guess your monitor may be polarised horizontally

After a basic search, vertical polarization for driving glasses would be correct. They work great at reducing reflections off the horizontal dash.

To add to the mystery, I checked another model of a monitor and my LCD TV and they are polarized the OTHER way. But side by side with the same image, I cannot tell the difference between the two monitors. You would never know unless you happened to have a polarizer on hand.