Wide Vs Narrow / standard Vs long lens camera and plate capture in less than ideal lighting conditions.

kamkar

kamkar

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10 years, many dashcams
Okay then poorly aligned and not that good focused long lens camera.

Anyways to the business at hand.

For a long time i have been telling myself that my long lens camera give me a much larger chance of a plate capture, not least in less than optimal weather.
So coming home from my drive today i got some of that footage, and what better excuse to crank up the newly updated editing suite and have a closer look.

First of all a little background information as we are after all talking about 2 different cameras and not to mention lenses.
So the SGGCX2 are more or less stock though it have another lens than the model are sold with, but the lens are still as wide as dashcam lenses go in the normal realm, the camera record 1080/30 footage and IQ / bitrate are set to high.
The SGGCX2 are equipped with the Sony IMX 323 sensor, not the top low light sensor out there, but still a okay one and i am sure it will be used for some time to come.
On the other hand we have my Mobius Maxi, it is equipped with a 12 mm lens for long range duty, but for this recording it are not in the sweet spot, but still good enough to confirm my suspicion, the Mobius record in 1080/60 and IQ / bitrate are also set to high.
For the 2 raw files the bitrate are SG 15.2 mbit / Mobius 26.1 mbit, so not the same bitrate.
Now you can argue well its 30 fps Vs 60 FPS, and thats also true, but i dont think the lighting are so low that the FPS settings have much affect on the suitable exposure timings the cameras can choose to use.
But just to be fair i will set the mobius to 1080/30 and a lower bitrate to be able to do a more potato Vs potato comparison in the coming days to make sure.

The sensor in the 2 cameras are also not the same, but here i think the Sony sensor in the SG camera have the upper hand on what is in the Mobius.

In my editing software i did a 5 second freeze frame on the one frame that was best for plate reading, this was much harder on the SGGCX2 where the Mobius i had several frames to choose from, and would have had even more if it had been aligned better in the L&R directions.
I still find this result interesting though it is not 100% fair in between the 2 contenders, so i will try to even the playing fiels out a bit more in settings and return with another video on the 2 cameras and their clody day / low light plate capture performance.

 
That would be much the same then i think maybe even worse then the X2, the X2 freeze frames 1 - 2 frames after that one and the plate are just a big blur, and going back in time then the cars have not yet entered the sweep spot for capture.

On the poorly aligned mobius i have almost taken the last pic before it leave the frame, but there are several before that work fine too, and it feel like the gap from "out there out of sweet spot " and until pass out if view are a bit larger.
Will have to remember to align the mobius camera better aside for dialing its settings back to look more like any other camera.
I do think it have something to do with the narrower angle the plates approach on the 12 mm lens, means the plate are "growing" in size as it approach, where as with the conventional lens the plate are speeding off to the side and out of view soon after it enter its plate capture sweet spot.
Still would have been cool to have a conventional mobius maxi there too, but i think it will behave the same as any other dashcam, cuz its not like there are some super sensor or secret sauce in the mobius, so if there are a difference i think it must be down to the lenses ( narrow Vs wide )
 
higher res, higher bitrate and frame rate should still help in those conditions even with the standard lens I would think
 
Now the Mobius are set back as far as i can, Normal bitrate ( lowest setting ) and 1080/30, and i have a excuse to soon go for a drive to visit Fie my girlfriend with 4 legs.
Wednesday look good for the same kind of weather.
 
Yeah, as we've seen in the "zoom lens" threads they do plate capture better, but if you have only one cam the wider-angle one will let the cam 'see' more traffic information which may be of greater relevance. Now that I've got the N2 in for testing and a working laptop for editing, if I can find the "X" cam mount here, I hope to get the varifocal Mobius in place. Or I may have to cobble together another hardware store mount for it. We've got at least 15 different plate styles in SC, and some of them are hard to read by eyeball, so it will be interesting what happens when I get it going.

Phil
 
O yes the long lens camera are worthless on its own, cars get out of frame way before they get to the side of your car.
But i feel it is the best add on outside of spamming your car with cameras, my front cameras are almost always where i get my footage for upload, and only once in a while spiced up with side camera footage.
 
Okay here i am back with a little more to contemplate.

First off the settings, the SG have not changed, but the mobius are now shooting 1080/30 too, but at a lower bitrate, about 10 mbit Vs the 15 the SG shoot at.
And sure enough plate capture on the long range did take a hit due to the now half bitrate, so really i must keep insisting on higher bitrates in dashcams, it just get so much better when it go up.
This bitrate issue i feel can also be seen at the end of the video, cuz what i did was put in a parking mode / hit and run emulation with me parked at the side of the highway where its only the other guys that do 80 km/h
And as soon as i was parked and so halving the total "collision" speed things got much better for both cameras, but the long lens mobius still got 2 X as many plate captures.

So i am feeling a lot better of my assumptions towards the long lens camera and plate capture in marginal conditions, and comaring the long lend camera performance yesterday Vs today it is clear to me the 2 X higher bitrate of yesterday did go a long way towards plate capture, i even think to a larger degree than the long lens do good.
So long lens are good for current conditions, but really would be rendered more or less mute if bitrates was ramped up in dashcams,,,, at least thats what i feel.

I have also been frame counting for today's recording, and overlaid the total number of frames with a good chance of plate capture, so thats the numbers you see in the footage.
And as always YouTube have degraded the video quality, so you cant really do any observations of your own based on my video.
 
kamkar1 said:
For a long time i have been telling myself that my long lens camera give me a much larger chance of a plate capture, not least in less than optimal weather.
So coming home from my drive today i got some of that footage, and what better excuse to crank up the newly updated editing suite and have a closer look.
Click to expand...
I like what you have done with the comparison video, despite the camera misalignment.

I think your early posts with the 12mm on the X camera were what got me into telephoto and varifocal lenses. I too believe that the longer lens is better for number plate capture, at least in some situations with oncoming traffic. When the road starts to bend cars very quickly come and go out of frame before you can get a decent look at them.

It's interesting that you have intentionally lowered the Maxi bitrate to try and level the playing field with the SG. I don't think I would have done that myself, so thanks for sharing your results.
 
It's clear that there is no beating a telephoto with high bitrate for details like plate capture. Paired with a good wide angle cam you get all that is possible to get :)

Now all we need to do is wait for Jokin to bring out an SG9999TW, with telephoto and wide-angle lenses together in one cam and a bitrate going like a Bugatti Veyron running wide open :love:

Phil
 
A dual camera with a wide and narrow camera both pointing in the same direction ( out front ) i would snag up in no time.
But this should also be doable with the dual remote systems if you mod the one lens, or SG or some one else decide to offer a optional tele lens.

I have set the Maxi up one level, so i can do a third run the day after tomorrow ( tomorrow are all sunshine they say )
But those dashcams with other means ot storage and the 18 mbits as the lowest IQ setting cant come soon enough if you ask me.
 
We have a couple of different camera options coming already, doing one with a different lens type wouldn't be that hard, finding the right lens is a bigger issue
 
jokiin said:
finding the right lens is a bigger issue
Click to expand...

We've seen that here with the several telephoto lenses tried out. Focusing at the factory might also be an issue; it wouldn't be very nice for a new cam to be out of focus :( Not sure of the market for something like this, but the "dashcam connoisseurs" among us would probably see it as a "must have". And you'd have that market all to yourself for awhile as nobody else seems to even have this concept on their radar right now. I can definitely see it as a remote cam option to be used with the "DR" main unit. Tons and tons of potential for that cam :)

Phil
 
Hehe yeah these days i dont even think some people stop to look if its actually selling, they will just go " hey why dident we think of that" and then go onto copy & sell mode.
A long lens night be okay to pair with a uber like camera or say like with the SGGCX2PRO.
So you can buy a camera on a long wire for a conventional front & rear dual channel, or front camera & camera with IR aid for a cabin uber camera , or front camera & a long lens for a dual front&front camera.
 
kamkar1 said:
Hehe yeah these days i dont even think some people stop to look if its actually selling, they will just go " hey why dident we think of that" and then go onto copy & sell mode.
Click to expand...

the copies often come out before the originals which makes matters worse, nature of the best unfortunately
 
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