Privacy dimmed glass - Camera view

[DJ70]

Thinking particularly about rear cameras (DR900X Plus-2ch), it occurred to me that the view obtained by the camera through a rear screen with deeply tinted glass must be considerably reduced.

I know this is very subjective, but has anyone had experience of using such a camera in a so-equipped vehicle and how does the image produced fair? Or to put it another way, is it actually worth having a rear camera in that situation?

It would be even better if anyone has images of such a setup.

 

[kamkar]

You can compensate for tint by changing the EV value for the camera behind it.
How much it help i have no idea as i have never tried it myself, but it should make things better.

 

[Nigel]

it occurred to me that the view obtained by the camera through a rear screen with deeply tinted glass must be considerably reduced.

The view is the same, just darker, which the auto exposure should correct so that the video is the same. The main difference is that due to needing longer exposure times, there is more motion blur, so if you have a tint that allows 25% of the light through, you will have 4x the motion blur. There will also be slight changes in colour/contrast, but they don't affect performance.

The normal use of a rear camera is to show that the car behind really did drive into you, and it doesn't take much image quality to show that, it is useful to have the plate of the car that drove into you recorded, but since it will probably be going roughly the same speed as you for some time before it fails to brake due to txting, motion blur isn't much of a problem. The only time it really is a problem is if you want to read rear plates on cars traveling in the opposite direction, then the extra motion blur will often make it impossible, if you live in a USA state without front plates then this is a disaster, in the UK it is normally not an issue since front cameras normally read the front plates better than rear cameras read rear plates.

So, you are better off with no tint or light tint, but even with 90% light reduction, a rear camera should still be useful.

I can't comment on the DR900X specifically, never tried one, but the physics is the same for all.

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[Dashmellow]

As @kamkar mentioned, you'll need to compensate for the dark tint by increasing the exposure value in your camera, but basically you should end up with serviceable results. The downside is that you will experience more motion blur in your videos due to the increased exposure times, but as @Nigel points out, with a rear facing camera this will be less of an issue than if it were on a front facing camera.

For many years I've had side facing cameras mounted in my pick-up truck which has darkly tinted rear fixed pane glass panels. I get excellent results in most situations where one needs a side camera, often even in fast moving traffic depending upon how close the target objects may be from the camera. Of course, this works quite well for parking mode. The point here is that shooting through tinted windows can work fine.

Here are some older examples with cameras I no longer have.

Here is the tinted glass I shoot through.


Here is an example of the results. (EDIT: the exposure was set +1/3 EV)


Using a dash cam behind dark tinted glass can have some interesting fringe benefits!
In the image below a guy is checking out the items on the rear seat of my parked vehicle yet he is completely unaware that there is a camera right in front of his face!

(EDIT: This is through the same passenger side rear window as in the above image but with a different camera.)

(

 

[kamkar]

You could also make a hole in the tint for the camera lens to see thru, i assume if it is a camera really close to the glass, the hole needed to be cut wouldn't have to be horrible large.
I think that is what i would do if i had that " problem "

 

[Dashmellow]

You could also make a hole in the tint for the camera lens to see thru, i assume if it is a camera really close to the glass, the hole needed to be cut wouldn't have to be horrible large.
I think that is what i would do if i had that " problem "

It depends on the type of tint. With a factory tint like in my vehicle there is no film to cut a hole in. The glass itself is tinted.

 

[kamkar]

Yeah that is of course a no go then with the scissors / X-acto knife,,, or blow torch.

I do think very few cars in the EU are sold with factory tented windows, i cant say i have ever seen a car advertised like that, then again it is also very rare i go looking for a new car.
It could possible be a option in the higher tier cars, or maybe it is more of a thing further south in the EU.
Here in Denmark you can tint as much as you like, that is aside for the front doors and windscreen, i think these are allowed with any degree of tint, but back doors and rear window,,,, knock yourself out.

TBH i dont think i would do anything to side windows, but on my rear window there is a chance i would do a cut out.

 

[Dashmellow]

i dont think i would do anything to side windows, but on my rear window there is a chance i would do a cut out.

My rear window has three panels with two fixed ones and a sliding glass panel in the middle. I installed a 4 inch piece of very dark tint film across the top of the center panel to hide the camera with a square hole for the lens to peek through. It works great, the camera is invisible it and looks good too. Here in my state, it is illegal to install tint in a vehicle but tint is legal if it comes from the factory. Nobody has ever bothered me about my self installed tint strip though.

 

[Nigel]

You could also make a hole in the tint for the camera lens to see thru, i assume if it is a camera really close to the glass, the hole needed to be cut wouldn't have to be horrible large.
I think that is what i would do if i had that " problem "

Only feasible for near vertical glass.

 

[Dashmellow]

Only feasible for near vertical glass.

Of course, my pick-up truck rear window is vertical but I think it would depend upon the rake of the rear windscreen, how close the lens is to the glass and the focal length of the lens. Conceivably, a truncated pyramid shaped hole in the tint film should work fine on a sloped glass with a downward tilted lens.

Many cars have built-in cameras that use truncated pyramid (trapezoidal) shaped openings to accommodate the angle of view of the lens on steeply raked windshields. Generally, these are part of a full built-in lens shade with a deeply recessed lens.
However, there seems no reason a dash cam with the lens reasonably close to the glass wouldn't work with a trapezoidal shaped hole cut into the tint film on a raked windshield.

When I cut a hole in the tint I used, it took a bit of experimentation and measuring, ultimately resulting in a horizontal rectangular shaped "hole" similar to the imaging ratio produced by the camera.

 

[rcg530]

One thing to keep in mind with the DR900X-2CH Plus dash camera, the firmware does not allow you to change the exposure levels for either camera. Pittasoft removed exposure related settings beginning with the "X Plus" series dash cameras. The other issue is that the rear camera (model RC110F) has a known issue in some lighting conditions (overcast skies) where it will darken/underexposre the rear camera footage far too much compared the front camera exposure level. I've been trying to get Pittasoft to fix this issue with the underexposed rear camera video for over a year now without success nor any promise of a fix any time soon.

 

[Dashmellow]

One thing to keep in mind with the DR900X-2CH Plus dash camera, the firmware does not allow you to change the exposure levels for either camera.

That's unfortunate. Personally, after experience with dozens of cameras over the years, not having manual control over the exposure would be a deal breaker for me. There are so many situations where this is necessary. For example, a car with a white hood in the image has a tendency to perform differently than a car with a black or dark blue hood on camera and the ability to adjust for this manually can make a huge difference in the results one achieves. Obviously, a rear camera can be different but since I drive a pick-up truck, the same issue is present depending upon what cargo is in the bed (or snow).

 

[KANNINA 2.0]

I live in Arizona and have the darkest rear tint I can get my hands on.

All the settings on my DR-900X-2CH are default, and it looks just fine:

Welp, Took It In the Rear Today [NSFW - Language]

Yellow lights are real short in Tucson, AZ. I slowed for the yellow at the upcoming intersection. Light was red a good 6 car lengths out. Douchenozzle behind me fully intended to run it. He ran after he hit me, and I chased him down. Mostly because he had a temp tag and I couldn't get close...

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[Nigel]

I live in Arizona and have the darkest rear tint I can get my hands on.

All the settings on my DR-900X-2CH are default, and it looks just fine:

As I keep saying, the auto-exposure should take care of it, so why do so many people, maybe the majority of posters, say that you need to adjust the EV setting? Which cameras have auto-exposure that doesn't work properly?

Good example video, I can't tell that you have any tint, the rear is actually brighter than the front ... rear camera still didn't read the licence number off the front of the car that hit you though!

 

[Dashmellow]

As I keep saying, the auto-exposure should take care of it, so why do so many people, maybe the majority of posters, say that you need to adjust the EV setting? Which cameras have auto-exposure that doesn't work properly?

Going back to at least 2012 I've experimented with at least 6 different brands and models of cameras shooting through darkly tinted windows. I learned that the need to manually compensate for the dark glass can vary significantly depending upon the characteristics of the particular camera. In some cases the camera merely attempted to faithfully reproduce the darker scene it was seeing. While all cameras will attempt to compensate automatically, the results were often improved when the camera EV was pre-set set to accommodate for the neutral density effect of dark glass.

Do you have any personal experience using dash cameras behind dark glass? I doubt it.

 

[Nigel]

the results were often improved when the camera EV was pre-set set to accommodate for the neutral density effect of dark glass.

So do you think that @KANNINA 2.0 's video could be improved by pre-setting the EV to accommodate for the neutral density effect of the dark glass?

What is a neutral density effect?

Do you have any personal experience using dash cameras behind dark glass? I doubt it.

All glass reduces the light level, being in the UK I'm limited to a minimum 70% light throughput, what do you consider to be dark?

I have used a rear view camera with a 0% rear view throughput if that counts, that is perfectly legal in the UK, and the auto-exposure failed to compensate!

 

[Lothar]

Good example video, I can't tell that you have any tint, the rear is actually brighter than the front ... rear camera still didn't read the licence number off the front of the car that hit you though!

Arizona does not require a front license plate.
There is no rear dashcam on the planet that can read something that does not exist.

 

[Dashmellow]

So do you think that @KANNINA 2.0 's video could be improved by pre-setting the EV to accommodate for the neutral density effect of the dark glass?

I have no idea Nigel, having never owned a DR-900X. You are well aware that I said that results can "vary significantly depending upon the characteristics of the particular camera". You're playing games here, which is always your standard approach when you have nothing intelligent to say or are dodging an answer.

What is a neutral density effect?

You are apparently playing games here too, but to answer your question, dark tinted glass works on a dash cam exactly like a neutral density filter on a standard camera.

All glass reduces the light level, being in the UK I'm limited to a minimum 70% light throughput, what do you consider to be dark?

Again with the coy game playing! You are well aware that the title of this thread you've been participating in all along includes the term "Privacy dimmed glass" and you've seen the image I posted above (and again below) of the dark tinted glass side window in my vehicle that I've been referring to.

Do you have any personal experience using dash cameras behind dark glass? I doubt it.

I have used a rear view camera with a 0% rear view throughput if that counts, that is perfectly legal in the UK, and the auto-exposure failed to compensate!

You could have simply answered my question with a straightforward "No", but of course that wouldn't be your style, especially when the question at hand calls you on your self appointed punditry wherein you make absolute assertions on subjects you have never had any personal experience with.

 

[DJ70]

One thing to keep in mind with the DR900X-2CH Plus dash camera, the firmware does not allow you to change the exposure levels for either camera.

I wondered when someone would spot that.

 

[Dashmellow]

I wondered when someone would spot that.

It's been interesting to learn this about the DR900X-2CH Plus. I've had hands-on experience with well over two dozen cameras during the last 12 years and can't think of another brand or model that hasn't offered some level of manual exposure control. While all dash cams control exposure automatically, the ability to override the default configuration can be vital for optimal performance. For example, as often discussed here on the forum, many owners find that the Viofo A119 V3 performs better set to -1/3 EV. Of course, as I've previously explained, the ability to adjust exposure for dark tinted glass is equally important if you want optimal results.