DIY (more like DIM) Dashboard Reflections' Eliminator

Module 79L

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Country
Portugal
Dash Cam
AT11DA, SG9665XS, G1W-H
Since I bought the G1W-H I've been a little "paranoid" about the dashboard reflections on the windscreen because I thought this camera picked them up more than the previous one, the G1W, until I realized (upon reviewing some "old" footage) that the reflections were already there, I just didn't notice them.

Then I saw somewhere here on the forum what could be a solution (sorry about my poor photographic skills):
IMAG0372.jpg IMAG0373.jpg

It's a ring cut from an old photographic roll box, which fits perfectly on the outside of the camera lens. I cut it as long as I could without interfering with the FoV and tested it on a sunny day (we've been having plenty of them lately). The results were disappointing, to say the least. The reflection's glare was a little attenuated but it did nothing to the reflections themselves. I even sandpapered the ring's interior to remove the gloss but to no avail.
But that wasn't the worst part: the worst part was that with the ring the "WDR" stopped working completely! There was little or no reaction to light changes from the camera.

So there was only one way to go: remove the source of the reflections. No, I didn't remove the dashboard or the windscreen, :D I just came up with something to eliminate the reflections.
I have some spare matte black cloth that we in the band sometimes use to cover things on stage, so I cut a strip long enough and wide enough to cover the whole dashboard, put it there, tucked it underneath the ventilation grid, and went for a test drive, with and without it.
Mind you that today the sky was mostly cloudy but I managed to get some sunlight exposure. These were the perfect conditions because I could see that even with low sunlight, the reflection was still there.
This was just a test, so nevermind the messy look:
Dashboard reflection terminator.JPG

The next step will be to cut it to fit and make it look as neat as possible.
I won't fix it permanently: I was thinking about putting some velcro only on the dashboard, because the cloth sticks nicely to the velcro, or just tuck it wherever I can. I don't mind if it doesn't follow the curves, since I don't use the dashboard tray anyway.
Now the snapshots:

BEFORE
Even in low sunlight conditions, the reflections can still be seen:
Before DRT-low sunlight_marked.png

Brighter sunlight. This one is pretty obvious:
Before DRT-bright sunlight.png

AFTER
I left a bit of the dashboard exposed on purpose to see if it still reflected on the windscreen. As you can see, it does but it's the only part reflecting:
After DRT-Reflection 1_marked.jpg
After DRT-Bright  sunlight 2.jpgAfter DRT-Reflection 2_marked.jpg


So, it works and didn't cost me anything. What more can you ask of a Did It Myself? ;)

Next I will try to get rid or at least attenuate all the windscreen chips.
 
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What is your Opel model / year ?
They do DashMats, but of course DIY solution is always more fun.
 
What is your Opel model / year ?
They do DashMats, but of course DIY solution is always more fun.
It's a 1997 Astra F Caravan and it's not mine. It's only the car I drive. ;)
I'd already seen it but that's not what I was looking for. Besides, it's only for other and older models.
User Dashmellow also posted a link to another company's site but they also don't have it (http://www.dashmat.com/products/index.phtml?prod_id=dashmat&cust_id=dashmat&SYSTEM=cartlink&SESSIONID=&ACTION=) and I was already working on this idea.
 
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For better results I think you'll need this: :D
I don't think I need to go that far. :D

There are some wrinkles on my "dashmat" but even they are not noticeable on the video.
 
It's a 1997 Astra F Caravan and it's not mine. It's only the car I drive. ;)
I'd already seen it but that's not what I was looking for. Besides, it's only for other and older models.
User Dashmellow also posted a link to another company's site but they also don't have it (http://www.dashmat.com/products/index.phtml?prod_id=dashmat&cust_id=dashmat&SYSTEM=cartlink&SESSIONID=&ACTION=) and I was already working on this idea.

I think what you did here is great and you probably don't need to improve on it. If you wanted to though, you could take a big piece of paper (like from a butcher's paper roll) and carefully make a template by marking and trimming it to match your dashboard and then cut the fabric to match the template. You could end up with a "dash mat" almost as nice as one of those commercial ones.

BTW, that was me who suggested making a G1WH lens hood from an old film canister. Specifically what I said was that it "will cut down on lens flare and "some" window reflections. I never suggested it would cure the problem. Lens shades do just that; they "shade" the lens from oblique light directly hitting the front lens element(s) (causing lens flare) or reflecting off of the inside of the lens barrel (reducing contrast).
 
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I think what you did here is great and you probably don't need to improve on it. If you wanted to though, you could take a big piece of paper (like from a butcher's paper roll) and carefully make a template by marking and trimming it to match your dashboard and then cut the fabric to match the template. You could end up with a "dash mat" almost as nice as one of those commercial ones.
I already did that: cut the excess cloth and tucked the edges wherever I could. I don't mind it looking a bit "amateurish", as long as it does what it's supposed to do. If it was my personal car, I'd probably make it look a little bit better. :)
I still have some "fine tuning" to do on some of the wrinkles but we haven't had much sunshine lately. In fact, it's been raining for the past 5 days, in sunny Portugal, in the middle of June!

BTW, that was me who suggested making a G1WH lens hood from an old film canister. Specifically what I said was that it "will cut down on lens flare and "some" window reflections. I never suggested it would cure the problem.
Thanks! I read that thread once but I couldn't find it again.

I didn't try it with that expectation either. I knew it wouldn't eliminate all the reflections and since I had a lot of those canisters "lying around", I decided to give it a try to see the results. After all, knowledge comes from experience. :)
What I wasn't expecting was how it affected the WDR, but I'm sure there must be an explanation for that, too.
 
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The WDR? Never experienced anything like that. I can't think of any logical reason a lens shade would or could do that.
 
I was as surprised as you are but the fact of the matter was that the sensor stopped reacting to light changes with the ring installed. At first I thought it may have been some one-off situation due to some particular weather conditions but it kept doing it in different days, so I removed the ring and it all went back to normal.
 
I was as surprised as you are but the fact of the matter was that the sensor stopped reacting to light changes with the ring installed. At first I thought it may have been some one-off situation due to some particular weather conditions but it kept doing it in different days, so I removed the ring and it all went back to normal.

Sounds weird to be honest with you. If the lens shade was not causing any vignetting and was not otherwise in the optical path of the lens it simply could not effect the functioning of the sensor.
 
I don't know much about photography, exposures or reflections but I'm thinking maybe it's like in audio with the omni-directional and uni-directional microphones, which is more my area of expertise. Without the ring the lens is able to capture light changes from every side at a 180º angle but even though the ring is only 1cm long, it probably blocks enough light to make the sensor react like there's no changes in it.
But that's just an uneducated guess.
 
I don't know much about photography, exposures or reflections but I'm thinking maybe it's like in audio with the omni-directional and uni-directional microphones, which is more my area of expertise. Without the ring the lens is able to capture light changes from every side at a 180º angle but even though the ring is only 1cm long, it probably blocks enough light to make the sensor react like there's no changes in it.
But that's just an uneducated guess.
It is quite common for the recorded image to be taken from the central part of the sensor image, either the central 1080 sized area or an area that is easy to scale to 1080, the ring may well have been blocking the light at the edges of the sensor image even though you can't see it in the recorded video and those edges may well have been used to calculate the exposure and WDR settings. You might be able to see it on a different resolution setting.
 
Update: replaced the pictures that were missing and added the long overdue view of the finished work, in this case, a video. :)
It was recorded with the G1W-H because of the narrower FoV.
 
It is quite common for the recorded image to be taken from the central part of the sensor image, either the central 1080 sized area or an area that is easy to scale to 1080, the ring may well have been blocking the light at the edges of the sensor image even though you can't see it in the recorded video and those edges may well have been used to calculate the exposure and WDR settings. You might be able to see it on a different resolution setting.
What if you drilled some holes in the ring to give the sensor a better chance of picking up light?
 
I have played with dashmats over the years and my latest & best evolution is a black commercial one. The fibres reflected somewhat so I sprayed into the pile with satin black paint (somehow reflects even less than matte black), laminated on the back with heat reflective foil, laminated on the foil with some of that non-slip rubbery plastic stuff which has holes all over (to dampen the foil from rattling and provide an air gap on the o.e. dash). With time these mats shrink so I slit mine fore/aft down the centre and trimmed the gap with a 3cm wide strip of black velvet, sprayed with the satin black.

My most effective 'mat was one I made with black velvet. It was a tedious effort and faded quickly

I've done similar for the rear window reflection using black felt. I cut the shapes (2 pieces for left & right) put newspaper on the shelf, wet the back of the felt with watered-down Aquadhere and arranged on the paper where it moulded nicely as it dried. Sprayed with satin black, laminated as above. It has held up perfectly for nearly 2 years but I got window tinting soon after.
 
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I've had pretty good results with a dashmat I bought, though I didn't realise when I ordered that it was coming from China. It wasn't a perfect fit, and I haven't even got around to tucking in the edges or using the supplied velcro to secure it. But it works well enough that I don't really need to worry about using my polarising filter (but I do when it's really bright.)
A pleasant bonus is no reflections to my eyes while driving - quite important for safety at times.

P.S. when I first discovered this mat on Amazon it was listed at full price, and I didn't think it was worth it. When it dropped to around half price I jumped at it.
 
A pleasant bonus is no reflections to my eyes while driving - quite important for safety at times.
That was also one of the the reasons that made me look for a dashmat. The car's dash is shiny black, made even worse by years of silicon spray use by the former owner.
 
I just received my first dash-cam, a mio mivue 658 (WiFi) and took it for a drive.
It was a bright sunny day. And with lots of reflection of my dashboard in the front window.
Looked so bad!

My solution:
I took a pair of glasses i received in my local 3d-cinema.
Then cut on of the glasses ( i was thin plastic ).
This material has polarization filter properties.
Using my scissors i cut a nice round slice just the size of the outer ring of my dash-cam.
I tested the orientation of the plastic so that all reflection was gone. Then "glued" it on
the outer ring of the camera using some silicone sealant normally used in sanitary rooms.
Crisp clear pictures are the result.

Advantage: filter is easily removable without leaving a trace.
Disadvantage: it dims the light a little. So at night it might be a not so good solution.

I will post demo on request.
 
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