CPL Status

Which is the good position, the bright image (first picture) or the dark image? Your lens is adjusted correctly in that position?

enjoy,
Mtz
Your TV should be designed so that you can see the TV image when wearing polarised sunglasses, polarised sunglasses and CPLs work the same way, so the good position is the first image where you can see the TV.

However it is easier to find the exact correct position if you rotate the CPL 90 degrees from normal and then choose the darkest position, then rotate it back exactly 90 degrees to give the correct clear position.
 
You are complicating the answer, maybe I wasnt clear.
Dark image = position OK ?
No matter if LCD is 45 degrees or 90 degrees.

The CPL lens can be easy adjusted when the films are not removed simply by holding the lens front and back with two fingers and rotate.

enjoy,
Mtz
 
Fit the CPL to the camera, point the camera at a TV (not a 3D TV), if the CPL is correctly adjusted then the image should be clear and it should turn black if you rotate the camera 90 degrees into portrait orientation.

If you are using a computer monitor instead of a TV then you need to worry about it possibly being at 45 degrees, you can check this using some polarised sunglasses, the camera with a correctly adjusted CPL should behave exactly the same as your sunglasses.
 
For the 45 degrees monitor I consider the Nikos guide to be good to follow.

enjoy,
Mtz
 
You are complicating the answer, maybe I wasnt clear.
Dark image = position OK ?
No matter if LCD is 45 degrees or 90 degrees.

The CPL lens can be easy adjusted when the films are not removed simply by holding the lens front and back with two fingers and rotate.

enjoy,
I think I will study up on dash mats covers that @Dashmellow has posted in depth. Maybe I can avoid a CPL altogether.
 
You just need to look at the two pictures from the guide and setup like there. Top picture is for dark CPL and bottom picture for clear CPL.
An easy way to obtain more reflections when outside is low light is to use your smartphone screen light to reflect on the windshield.

enjoy,
Mtz
 
Guess it has to be a tv screen then.....The glass on my phone screen must be polarized in some fashion, so it wont work for this trick...with my sunglasses on and screen at full brightness , in portrait mode, the screen is quite dark, when i rotate phone to landscape, it goes completely black. I cant use my phone in my car for gps while wearing sunglasses...grrrr.
 
a VERY simple solution was given earlier in the thread - put a plain white sheet of paper on your dashboard, then turn on the camera, and adjust the CPL till you don't see the reflection of the paper anymore. done. no need for TVs, monitors, or any special knowledge about which way things are polarized.

if you feel the need to use glue to secure the CPL after adjusting it, DO NOT use super/krazy/gorilla-glue (or any other "instant" type glue that contains CyanoAcrylate - the kind that bonds skin instantly) - that will cause permanent damage (fogging) to the CPL and probably to the dashcam's lens coatings as well. instead use something less aggressive, like hot glue, school glue, or even Silicone RTV (gasket material). whatever type of adhesive you use, try to use as little as possible so that if you accidentally knock it out of adjustment while gluing it, you can remove the glue and try again.
 
a VERY simple solution was given earlier in the thread - put a plain white sheet of paper on your dashboard, then turn on the camera, and adjust the CPL till you don't see the reflection of the paper anymore. done. no need for TVs, monitors, or any special knowledge about which way things are polarized.

if you feel the need to use glue to secure the CPL after adjusting it, DO NOT use super/krazy/gorilla-glue (or any other "instant" type glue that contains CyanoAcrylate - the kind that bonds skin instantly) - that will cause permanent damage (fogging) to the CPL and probably to the dashcam's lens coatings as well. instead use something less aggressive, like hot glue, school glue, or even Silicone RTV (gasket material). whatever type of adhesive you use, try to use as little as possible so that if you accidentally knock it out of adjustment while gluing it, you can remove the glue and try again.

You read my mind here @Gibson. I've been thinking basically the same thing and was going to post on the subject. There is no need to make oneself crazy with all this LCD monitor business. Just adjust the camera accordingly in real time in your vehicle. Over the years I've been messing around with dash cams I've had good success parking my vehicle in a place where I can invoke a bad windshield reflection and then using the built in LCD monitor right on the camera to adjust the CPL. Placing a reflective object like a white sheet of paper on the dashboard is a good enhancement tool for the job.

As for securing the CPL in place in a reversible, non-destructive manner my preference has been to use a tiny wad of strategically placed Blu-Tack. This is useful if you need to tweak the CPL adjustment or perhaps may want to eventually use the camera in a different vehicle that has a different windshield shape and rake.

And YES, by all means stay away from super-glues anywhere near any and all optical surfaces.
 
The reflecting smartphone light from display method is good for darker days, just test it. You can use just the dashcam screen because can not be perfect about 10 degrees angle. It is not like focusing the lens, the CPL alignment is much easy.
It is not necessary any glue for CPL lens, the filter is hard to be rotated.

It is easy to use the @niko idea just because when filter is new you can put the fingers right over the filter and more easy to rotate compared to mounted filter. After adjusting it you can remove the protecting films.

enjoy,
Mtz
 
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a VERY simple solution was given earlier in the thread - put a plain white sheet of paper on your dashboard, then turn on the camera, and adjust the CPL till you don't see the reflection of the paper anymore. done. no need for TVs, monitors, or any special knowledge about which way things are polarized.

if you feel the need to use glue to secure the CPL after adjusting it, DO NOT use super/krazy/gorilla-glue (or any other "instant" type glue that contains CyanoAcrylate - the kind that bonds skin instantly) - that will cause permanent damage (fogging) to the CPL and probably to the dashcam's lens coatings as well. instead use something less aggressive, like hot glue, school glue, or even Silicone RTV (gasket material). whatever type of adhesive you use, try to use as little as possible so that if you accidentally knock it out of adjustment while gluing it, you can remove the glue and try again.


That is the point. Quadratisch. Praktisch. Gut." ("Square. Practical. Good.") as in German chocolate Ritter Sport means do not to complicate easy things. There is not NASA project (TV, LCD, DVD, MD, ... SW Millennium Falcon) only white sheet of paper on your dashboard ... it works perfecly.
 

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If you are using a computer monitor instead of a TV then you need to worry about it possibly being at 45 degrees,

45, vertical or horizontal, (some are said to be at 135 but I haven't seen that), amongst 8 monitors I have 3 different directions to deal with, there's no real reference to know what you have either, the sunglasses method is probably the easiest way to check, polarised sunglasses are apparently all in the same direction regardless
 
polarised sunglasses are apparently all in the same direction regardless
They wouldn't remove the windscreen reflections if they made them at any other angle; I wouldn't be surprised if some of the cheap ones are wrong though!
 
Which is the good position, the bright image (first picture) or the dark image? Your lens is adjusted correctly in that position?

enjoy,
Mtz

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I am have a 3-D TV at home. Is it same as the normal TV to adjust the filter?
 
I am have a 3-D TV at home. Is it same as the normal TV to adjust the filter?

I googled around and it's unclear. If you have any polarized sunglasses, see if they behave like my previous post example.
 
After test with a TV, and found the darkest and clearest position. Should I use the darkest one or the clearest one to use on the PCL? Someone told that the darkest one is the most effective one to block reflection.
 
After test with a TV, and found the darkest and clearest position. Should I use the darkest one or the clearest one to use on the PCL? Someone told that the darkest one is the most effective one to block reflection.

the blackout happens at 90 degrees from where it would be when installed in the example that @Street Guardian USA posted earlier
 
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