A129+ with cpl, better 30 or 60 fps?

[Robonus]

Hey,

I'm thinking of buying the A129 Plus Duo, and adding a cpl filter to the front cam (i don't want a dashmat).
Main reason i was looking into the A129+ is that it can record 2K@60 fps. My thought here was that with 60 fps you get more frames. So if a oncoming car is within "licence plate reading distance" for, lets say, 0.2 seconds, you get more frames to read the license plate than with 30fps. Also the shutterspeed has to be faster with 60 fps so in theory the image should be less smeared, thus more readable. Can anyone confirm if my conclusions are plausible?

Then the second question, a cpl filter always absorbs some of the incoming light, leaving less light for the imagesensor. So would it be wise to add a cpl filter with 60 fps for night conditions? Has anyone tried that? Or is 60fps killing for nighttrips because half the light is available for every sensorpixel (compared to 30fps)?

And a third question, maybe not in the right topic, but the70mai A800S is available for just 97 euros on Ali, that's almost 50 euros cheaper than the A129plus atm (€144.95 in Netherlands)
It has a 4K sensor but in comparison video's i've seen that the A129+ had better license plate readability on fast moving cars. Theory is that the incoming light is divided over more pixels, leaving less light per pixel. Would the 800S maybe be better when set to 2K@60FPS?

 

[kamkar]

It is true a CPL take a little light, but not a problem today really.
The A129 plus duo will always log what you do with your car, and it will do that 100 % no matter the lighting conditions, only really thick fog or severe snowfall will change that fact.
And like with any other camera CPL or not, capturing small details in low light, and not least at speed, well it will still be a major problem / next to impossible.

I would not run 60 FPS on a dashcam, if you want cinematic footage, or at least footage that look more like that, you need to consider another camera system, a dashcam are just a accident recorder and as such 30 FPS are fine.
60 FPS will also mean at night the camera can not drop to as slow exposure times as it would like to, though it dont really matter as exposure times of 1:30 or 1:60 second are far too slow for anything moving faster than a baby can crawl, and is why you always see motion blur in low light footage.
To get a chance of a crisp image at something moving at speed, or captured from something moving at speed, the exposure time should at least be 1:500 second.

With the new 70mai cameras you also get a annoying ( well to some ) brand watermark you can not remove, setting to a lesser resolution just mean you film that resolution with the same small pixels, it would only be good if the camera did like phone cameras do for night pictures where it bin 4 or more pixels into 1 far more light sensitive larger pixel.
so for in stance my phone camera take 64 mpix day shots, but using same sensor only take 12 pmix night time photos ( binning 4 sensor pixels into one )

 

[HonestReview]

Hey,

I'm thinking of buying the A129 Plus Duo, and adding a cpl filter to the front cam (i don't want a dashmat).
Main reason i was looking into the A129+ is that it can record 2K@60 fps. My thought here was that with 60 fps you get more frames. So if a oncoming car is within "licence plate reading distance" for, lets say, 0.2 seconds, you get more frames to read the license plate than with 30fps. Also the shutterspeed has to be faster with 60 fps so in theory the image should be less smeared, thus more readable. Can anyone confirm if my conclusions are plausible?

Then the second question, a cpl filter always absorbs some of the incoming light, leaving less light for the imagesensor. So would it be wise to add a cpl filter with 60 fps for night conditions? Has anyone tried that? Or is 60fps killing for nighttrips because half the light is available for every sensorpixel (compared to 30fps)?

And a third question, maybe not in the right topic, but the70mai A800S is available for just 97 euros on Ali, that's almost 50 euros cheaper than the A129plus atm (€144.95 in Netherlands)
It has a 4K sensor but in comparison video's i've seen that the A129+ had better license plate readability on fast moving cars. Theory is that the incoming light is divided over more pixels, leaving less light per pixel. Would the 800S maybe be better when set to 2K@60FPS?

A129 Plus Duo Dual Channel Dash Cam Front 2K 1440P + Rear 1080P Wi-Fi GPS Dash Camera

VIOFO A129 Plus Duo Dual Channel dash cam supports 2K 1440P 30fps video recording, it takes Sony Starivs sensor for front and rear.

www.viofo.com

60 FPS is not supported if using two cameras. It's 2K 30 FPS and 1080p 30 FPS rear.

 

[kamkar]

O that too, most dual systems the 60 FPS that can be done on front camera are only that camera alone, or maybe that camera running a lesser resolution than the full one.

 

[HonestReview]

O that too, most dual systems the 60 FPS that can be done on front camera are only that camera alone, or maybe that camera running a lesser resolution than the full one.

Ya im not aware of any cameras doing 60 FPS in a two or three channel setup.

 

[Robonus]

Good to know, thanks for the extra information!
An irremovable watermark would be a no-go for me so that eliminates the 70mai A800S

Tak for hjælpen
Tack för hjälpen

;-)

 

[kamkar]

70 mai users have only figured out how to remove those on older models, with a modified firmware i assume, no word of that happening for the new models yet.

 

[Nath]

Ya im not aware of any cameras doing 60 FPS in a two or three channel setup.

Viofo A139 does 1440p/60FPS in 2CH. But, at least for now, not worth it - reducing brightness without any significant pros, it will be interesting in case of HDR (it still be 30fps, but the ability to shoot 60fps is precondition for "inter-frames"), if ever will be implemented.

 

[HonestReview]

Viofo A139 does 1440p/60FPS in 2CH. But, at least for now, not worth it - reducing brightness without any significant pros, it will be interesting in case of HDR (it still be 30fps, but the ability to shoot 60fps is precondition for "inter-frames"), if ever will be implemented.

Interesting. According to you though, using 60 FPS on the A139 offers little benefit and causes worse video quality.

 

[Nath]

Well, it noticibly reduces exposure, "worse video quality" is probably not the case, at least not right off a bat. But it uses h.264 for 60fps(200MB/min) and h.265 for 30fps(173MB/min) at max, so in side-by-side comparison it could show some differences.

 

[HonestReview]

Well, it noticibly reduces exposure, "worse video quality" is probably not the case, at least not right off a bat. But it uses h.264 for 60fps(200MB/min) and h.265 for 30fps(173MB/min) at max, so in side-by-side comparison it could show some differences.

Is the 60 FPS more grainy with less exposure or just darker?

 

[Nigel]

Also the shutterspeed has to be faster with 60 fps so in theory the image should be less smeared, thus more readable. Can anyone confirm if my conclusions are plausible?

The shutter speed can be the same on both, eg 1/2000th second will give exactly the same amount of motion blur at 60fps and 30fps.

The readability may differ since 60fps will need a higher bitrate to store all the frames. If the bitrate used is the same for both then readability may be worse on the 60fps since it is using more bitrate for temporal resolution leaving less for spatial resolution. No cameras give twice the bitrate for 60fps, or anywhere near that.

60fps makes better movies because the movement looks smoother, but it adds little to the information needed from an accident camera, and on many cameras the increase in bitrate for the 60fps mode is inadequate to avoid an increase in image pixelation.

So would it be wise to add a cpl filter with 60 fps for night conditions? Has anyone tried that?

It does not help, generally it cuts out about half the light, which equals twice the motion blur, and motion blur tends to the the limiting factor at night.

However, the advantages of a CPL can vastly outweigh the disadvantages, depending on how prone to reflections your car is, and that can vary quite a lot between cars.

Or is 60fps killing for nighttrips because half the light is available for every sensorpixel (compared to 30fps)?

The same amount of light is available for both 30 and 60fps, unless there is not enough light for an exposure faster than 1/60th second, in which case the motion blur is going to be so great that it is not worth worrying about being able to read plates anyway, and it would be a good idea to turn your car headlights on!

The exception is if you are parked in a dark place and want to record moving cars, but that does not work well anyway in most cases.

Would the 800S maybe be better when set to 2K@60FPS?

If you want to record 2K, it is better to use a 2K sensor, so there is 1 sensor pixel for each image pixel. Using a 4K sensor for 2K recording means that for each image pixel there is 1.something sensor pixels, not an exact division by 2, so you cause some image blurring when scaling the image. Also 4K sensors are normally a little less sensitive than 2K sensors so will have a little more motion blur.

For European license plates, 2K resolution is sufficient, 4K resolution is still nice for making moves, but not necessary for accident evidence.

 

[ursamajor]

OP,

Bare in mind... CPL filter takes 1 maximum 2 stops of light, not half of the light as some say.
The advantage of CPL is that it eliminates parasit light, not the useful light. All non-metallic reflexions will be eliminate (or at least strongly athenuate), including reflexions of suspension particles in the air, as a consequence sky will be real blue, not white-light blue.
30fps vs 60fps is a matter of choice. 60fps will show you video more cursive. 30fps maybe will show you car plates, but only marginal better.

 

[HonestReview]

OP,

Bare in mind... CPL filter takes 1 maximum 2 stops of light, not half of the light as some say.
The advantage of CPL is that it eliminates parasit light, not the useful light. All non-metallic reflexions will be eliminate (or at least strongly athenuate), including reflexions of suspension particles in the air, as a consequence sky will be real blue, not white-light blue.
30fps vs 60fps is a matter of choice. 60fps will show you video more cursive. 30fps maybe will show you car plates, but only marginal better.

You cannot use the CPL filter on tinted windows unless you want a starburst effect. Learned this from trial and error.

 

[ursamajor]

Not CPL problem if they have tinted window.

 

[Nigel]

Bare in mind... CPL filter takes 1 maximum 2 stops of light, not half of the light as some say.

1 stop is half the light

You cannot use the CPL filter on tinted windows unless you want a starburst effect. Learned this from trial and error.

Most tinted windows work OK, some will cause rainbow effect, depending on the technology of the tint.

 

[ursamajor]

Indeed, my fault, it doubles the exposure time (if gain is constant*, but I doubt). But, like I said, it removes only parasit light, so, it is closer to reality than with reflections of windshield. It's like the windshield is bypassed or... removed.

* I noticed in my tests that CPL filter doesn't seem to increase dramatically exposure time, probably camera firmware keep it low by increasing the gain/ISO.

 

[HonestReview]

1 stop is half the light


Most tinted windows work OK, some will cause rainbow effect, depending on the technology of the tint.

Ceramic Tint does not play nice with the CPL filter. I tried every method from turning the lens to repositioning camera. Starburst effect / Rainbow effect is an unfortunate byproduct. Ended up removing CPL filter as a result.

 

[kamkar]

I remember the old days when people was at least considering taking the CPL filter off at night.
Personally if i have gotten a camera with a filter i have put it on, even if i have my DIY dashmat and it is no longer absolutely needed.

And i think most cars need a CPL filter on a dashcam you put in the car.

 

[HonestReview]

Not CPL problem if they have tinted window.

True but it is worth noting and telling people who do have tinted windows, like myself.