How is the video quality for you guys ?

[DT MI]

Yes, that could be a good solution.

In professional photography and cinematography this is accomplished with the use of graduated ND filters. (ND=neutral density)....

That's where the idea came from - many years of 'semi-professional' photography (got paid for 2 shoots so that's pretty 'semi' ).

Haa there goes my business idea of using sharpie and plexi glass to cut to size and use lol... didnt know they already got something like that.. does amazon carry these things ?

You could try getting some 'gels', much cheaper than true ND filters and can be cut to size and/or stacked if wanted. Probably not a good permanent solution but you never know until you try. Get a set with a lot of darker colors to minimize or eliminate the need for stacking.

Amazon.com : color gels for photography

 

[Dashmellow]

Yes, gels can work. Just cut a piece and position it carefully part way down from the top of the lens. You might need to fashion a filter holder to position the gel far enough away from the front lens element so that the filter creates a smoother more graduated transition between the filtered sky area and the unfiltered lower part of the view.

Even if a gel won't last forever they are cheap enough to replace with a new piece of gel,

What you would want to purchase are Neutral Density Gels which will not affect the color balance of the image and come in different density values. (ƒ/ stops)

Norman Pack of 3 Neutral Density 810551 Filters (5")

Buy Norman Pack of 3 Neutral Density 810551 Filters (5") featuring Replaces ND5. Review Norman ND5

www.bhphotovideo.com

 

[DT MI]

...Neutral Density Gels...

ND gels never came to mind since I've only used gels for color correction/modification.

Available on Amazon as well - and cheaper than pro grade Norman's which for this application might well be a bit of overkill.

https://www.amazon.com/s?k=Neutral+Density+Gels&ref=nb_sb_noss_2

 

[Nigel]

What is the purpose of the filter?

The only effect should be to avoid overexposure of the clouds , which may improve the video but often looks rather odd and doesn’t help with evidence gathering.

 

[DT MI]

What is the purpose of the filter?

The only effect should be to avoid overexposure of the clouds , which may improve the video but often looks rather odd and doesn’t help with evidence gathering.

The primary effect is to avoid the overexposure of the clouds, which in turn causes the AE logic in the camera to underexpose the rest of the frame thus potentially not recording something important - such as plate numbers in the OP's example.

A tutorial on ND filters:

Using Graduated Neutral Density Filters

www.cambridgeincolour.com

 

[kamkar]

Graduated ND filters you might be able to find for action cameras or drones i am sure i have seen some, my osmo action use round screw on filters that i assume could be modified to work on a action camera

A picture of the A139 CPL with the CPL filter from the 4 pack ND + CPL filters ( freewell ) for my osmo action camera, if the A139 had thread in the outside there the original filter screw on, you could probably screw a ND filter onto there it is that close to be the same, but the freewell filter can not be pressed on the A139 as is, it ( A139 ) will have to be shaved a little to do that.

 

[Dashmellow]

I used to have a windshield that had a 5 inch blue tinted strip along the top of the glass that gradually transitioned to clear glass just like one of these graduated neutral density filters we're talking about. I found that I could mount dash cams in a position where the lens was just peeking out from slightly below the tint strip where it would cover the uppermost section of the angle of view exactly like a graduated filter. This worked quite well to improve the overall exposure during bright sky situations and didn't particularly effect the image quality at other times. The effect was virtually seamless and nobody viewing my footage would even know the top part of the image was being filtered. The tint strip also had the fringe benefit of hiding the camera from view, thus making for a stealthy installation.

 

[Nigel]

The primary effect is to avoid the overexposure of the clouds, which in turn causes the AE logic in the camera to underexpose the rest of the frame thus potentially not recording something important - such as plate numbers in the OP's example.

The AE logic should not be affected on the Viofo A139, on dashcams AE does not normally base exposure on the clouds, unless you point the camera too high.

 

[mrpk]

I gotta try the gels, what you do stick them on the lens with glue or something ? How would you keep them in place?

 

[Dashmellow]

I gotta try the gels, what you do stick them on the lens with glue or something ? How would you keep them in place?

If you have some DIY skills you might try to construct some sort of filter holder. Other than that I would recommend just using some tape. Even some clear cellophane type tape will do. That way it will be easy to remove, adjust or replace the gel.

 

[Nigel]

I gotta try the gels, what you do stick them on the lens with glue or something ? How would you keep them in place?

It may be easier to stick them on the glass, some people get the correct effect from sun strips on the glass, it needs a much larger filter to do that, but to just do the top of the image doesn't need to be huge, the bottom would be huge but not the top because the glass is a lot closer. You can also use window tinting film stuck to the glass, again it doesn't need a huge amount and it can also be used to hide the camera. Because it is close enough to be out of focus, you don't need it to be particularly neat for a decent image.

 

[DT MI]

The AE logic should not be affected on the Viofo A139, on dashcams AE does not normally base exposure on the clouds, unless you point the camera too high.

Well it's pretty obvious that 'something' is causing most of the frame in the OP's example to be underexposed coincidental with the grossly overexposed sky/clouds.

Since you're sure that it's not the AE logic of the A139 what is your newly found expertise (based on the fact that 8 posts back you didn't even know the function of an ND filter) saying the cause might be? And while you're at it can you provide us with the exposure mapping of the A139 so the rest of can understand how you came to your conclusion?

 

[Nigel]

Well it's pretty obvious that 'something' is causing most of the frame in the OP's example to be underexposed coincidental with the grossly overexposed sky/clouds.

There is a problem with dashboard reflections in the windshield, but if they weren't there, would this be pretty obviously overexposed?

 

[DT MI]

There is a problem with dashboard reflections in the windshield, but if they weren't there, would this be pretty obviously overexposed?

View attachment 58354

Based on my experience (both with dash cams and photography in general) - Yes.

Now, how about answering the questions I asked - if you can.

 

[Nigel]

Based on my experience (both with dash cams and photography in general) - Yes.

Apart from a small area around the sun, and the sun itself, there is very little there that is sufficiently overexposed to have no detail, and almost no camera can expose the sun well enough to record sun spots while also recording detail in the shadows behind vehicles. Also the purpose of a dashcam is not to record sunspots, apart from the position of the sun and the cloud coverage, the detail of the sun is not important evidence, so as a dashcam image, I don't think that is overexposed.

Next question, is it underexposed?

Of course if you answer yes, then you are saying that it is both pretty obviously overexposed and underexposed...

 

[Dashmellow]

I gotta try the gels, what you do stick them on the lens with glue or something ? How would you keep them in place?

@mrpk, I was browsing AliExpress for reasons unrelated to this thread when I came across various graduated ND filters selling at very low prices. These would be ideal for your needs as they could be cut to size without much concern for the costs involved. These would likely be a better solution than the solid gels and they are cheaper than the price of the gels on Amazon.

The cheapest item seems to have long shipping times but the same seller offers a whole graduated ND filter set for $7.49 USD with faster shipping. Might be something to consider?

https://www.aliexpress.com/item/32710187671.html?spm=a2g0o.productlist.0.0.3ac17f3ap7d1N8&algo_pvid=24ce79bf-9cfd-4bc8-abff-6dd7740eccf6&algo_exp_id=24ce79bf-9cfd-4bc8-abff-6dd7740eccf6-3&pdp_ext_f={"sku_id":"60907433361"}

https://www.aliexpress.com/item/32797286317.html?spm=a2g0o.detail.1000060.1.75633cb1yEn8z6&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.169870.0&scm_id=1007.13339.169870.0&scm-url=1007.13339.169870.0&pvid=016eec78-2748-42ad-8776-b979a6bf6fb7&_t=gps-id😛cDetailBottomMoreThisSeller,scm-url:1007.13339.169870.0,pvid:016eec78-2748-42ad-8776-b979a6bf6fb7,tpp_buckets:668#2846#8115#2000&&pdp_ext_f={"sceneId":"3339","sku_id":"64109472061"}

 

[mrpk]

Tomorrow morning guys going to try the CPL filter, also have placed the camera at a different location, kinda had a camera dismount accident lol, so there is that. Got my interior camera too now mounted temporary till the velcro falls from the roof cloth surface, it's going to act as my blind spot checker. Let's see how the video quality is tomorrow with all 3 channels 🙂.

 

[mrpk]

Server going some migration, so no point ftping the videos, but the filter just makes it darker, no glare resolution, puts strain on getting the license plates. Guess it is what it is, one cannot predict the sun's location. Waiting on my longer cable for interior cam, so i can point it better to the traffic on passenger side of things.. kinda did not work today again too much sun and shadows ... will see.. where to stick the interior cam to get better road visibility on passenger side.

 

[Nigel]

Server going some migration, so no point ftping the videos, but the filter just makes it darker, no glare resolution, puts strain on getting the license plates. Guess it is what it is, one cannot predict the sun's location. Waiting on my longer cable for interior cam, so i can point it better to the traffic on passenger side of things.. kinda did not work today again too much sun and shadows ... will see.. where to stick the interior cam to get better road visibility on passenger side.

Filter is supposed to remove reflections, may also increase contrast a little, and turn the sky more blue, that is about it.

 

[mrpk]

Filter is supposed to remove reflections, may also increase contrast a little, and turn the sky more blue, that is about it.

Well that sucks.. I thought filter be the solution. Hmm I am now debating do I need expensive 3 channel cam or shall I get the cheap 3 channel cam.. cost close to over 300. If all cameras suffer from same issues why not get cheap one lol..damn.. I have not done any night driving and I am guessing it be same, no license plates at night or poor video with on coming headlights