proposed license plate camera hack.

nighttime test footage with exposure set to -2.
Reducing the exposure to -2 does reduce the likelihood that a license plate is over exposed into oblivion, but it does not seem to reduce the exposure time at all.
If you compare this to my test at the default exposure the smear of cars crossing the intersection seems about the same length (freeze frame). They must be reducing the exposure by decreasing the gain.
The 12mm camera does definitely increase the number of plates that can be read over the main camera, but only for cars traveling the same direction. Look specifically at the cars in the right lane near the beginning of this video. They are clearly visible with the 12mm lens, but a blurry mess in the main camera video, even though they are large enough that the numbers should be legible.
Youtube is estimating the upload will complete in 17 minutes.
 
Reducing the exposure to -2 does reduce the likelihood that a license plate is over exposed into oblivion, but it does not seem to reduce the exposure time at all.
If you compare this to my test at the default exposure the smear of cars crossing the intersection seems about the same length (freeze frame). They must be reducing the exposure by decreasing the gain.
When the ambient light is this low the camera is likely to be at its exposure limit of 1/30s per frame, so the motion blur will be the same no matter what exposure compensation is set. And yes, the exposure will be adjusted by decreasing the gain.
 
When the ambient light is this low the camera is likely to be at its exposure limit of 1/30s per frame, so the motion blur will be the same no matter what exposure compensation is set. And yes, the exposure will be adjusted by decreasing the gain.
Looking at the video, the exposure time is 1/30th, you can easily measure it by the amount of motion blur on the crossing vehicles being equal to the distance traveled between frames, but the camera could presumably have increased the shutter speed to 1/120th to implement an EV of -2 instead of decreasing the gain...

I suspect the EV always works by adjusting gain, though it is hard to tell in good lighting, and if you can't tell then it doesn't really matter!
 
I will add one additional observation. When running both the front camera and the rear camera, the A129 pro duo gets REALLY hot. Pulling the memory card, it is almost too hot to hold. The only reason I can hold it is because it has so little thermal mass that it cools down quickly.
I think there might be a market for a heat pipe and heat sink that sits between the GPS and the camera, and sticks the heat sink fins out to the side.
I am debating if it is a good idea to keep that rear camera connected.
There was a video of someone testing the heat handling of the A129 pro camera a while back. I don't remember the rear camera being connected. I think that test needs to be re-done with the rear camera attached. I'm not so sure it would pass.
 
The only reason I can hold it is because it has so little thermal mass that it cools down quickly.
The reason it feels so hot, but only for a short period, is that by design it has a very high thermal conductivity. The card itself is effectively a heatsink to pull the heat away from the memory chip embedded inside it. Almost as conductive as metal. If you use an IR thermometer on it then it is hard to get a reading that says "hot".

The A129 Pro does write a lot to the memory card, it does heat up. The internal heat sink/spreader does collect heat from the card area, not too easy to improve things.

I am debating if it is a good idea to keep that rear camera connected.
There were a few issues with early units, especially when used for parking mode, but I've not seen reports of overheating for ages. They seem to have made them reliable, so I don't think there is any reason to worry. Given your location, I'm not sure using them for parking mode is a good idea, with or without the rear camera.
 
I measured the temperature of the A129 Pro Duo today with a non-contact thermometer. I got 58 degrees C on the outside of the case.
 
I have an old A119 V2 camera that has gone flaky (randomly silently stops recording) and another 12mm lens. Since the camera is not usable, but works for a while, I will use it to test putting the 12mm lens in it.
This camera uses the same lens mount as the A129 pro (19mm screw spacing, and too short threaded tube) so I will have to make another spacer. When I have it done, I'll report the results in the A119 thread.
 
Wondering if I can transplant a 6mm F1.2 lens into the A139 interior camera...
PXL_20221029_172143388-01.jpeg
 
Wondering if I can transplant a 6mm F1.2 lens into the A139 interior camera...
View attachment 62172
Probably. That mount looks different than the one used by the A129 pro reverse camera, or the one used by the A119 V2, so it may be one of the two standard screw spacing mounts instead of the oddball 19mm mount that the A129 and A119 use (you can measure the screw spacing without disassembling it more than you already have). If it is not 19mm, you can buy alternate mounts on Amazon. The reason you might need an alternate mount is that some lenses will not focus in the range of distances allowed by the existing mount. Longer focal length lenses want to be further from the sensor than the original short focal length lens. If you do need to change the mount, you will have to remove that RF shield which may require soldering.
If you are lucky, you will just unscrew the original lens (chip away the glue holding it in focus first, then install the new lens and see if you can get it in focus. If it focuses only with you holding the lens in front of the mount, you will need to modify the mount. If it focuses at least 1mm in front of the mount, you may be able to use an extender tube.
Good luck.
 
Wondering if I can transplant a 6mm F1.2 lens into the A139 interior camera...
View attachment 62172
Probably won't focus without a mount extender to add some thread, the lenses on these cylinder shape rear Viofo cameras are a closer focus than the front camera lenses.
 
Probably won't focus without a mount extender to add some thread, the lenses on these cylinder shape rear Viofo cameras are a closer focus than the front camera lenses.
I have a spare mount extender just in case. The housing was fairly easy to work with, and I can test the new lens focus without having to reassemble it, which is not the same with the more complicated front cameras.
 
Probably. That mount looks different than the one used by the A129 pro reverse camera, or the one used by the A119 V2, so it may be one of the two standard screw spacing mounts instead of the oddball 19mm mount that the A129 and A119 use (you can measure the screw spacing without disassembling it more than you already have). If it is not 19mm, you can buy alternate mounts on Amazon. The reason you might need an alternate mount is that some lenses will not focus in the range of distances allowed by the existing mount. Longer focal length lenses want to be further from the sensor than the original short focal length lens. If you do need to change the mount, you will have to remove that RF shield which may require soldering.
If you are lucky, you will just unscrew the original lens (chip away the glue holding it in focus first, then install the new lens and see if you can get it in focus. If it focuses only with you holding the lens in front of the mount, you will need to modify the mount. If it focuses at least 1mm in front of the mount, you may be able to use an extender tube.
Good luck.
I don't plan to replace the lens mount, only to use an extender if necessary. I think this 360 rotating constant friction mount will be better for a telephoto than the A129 rear camera units.
 
Probably. That mount looks different than the one used by the A129 pro reverse camera, or the one used by the A119 V2, so it may be one of the two standard screw spacing mounts instead of the oddball 19mm mount that the A129 and A119 use (you can measure the screw spacing without disassembling it more than you already have). If it is not 19mm, you can buy alternate mounts on Amazon. The reason you might need an alternate mount is that some lenses will not focus in the range of distances allowed by the existing mount. Longer focal length lenses want to be further from the sensor than the original short focal length lens. If you do need to change the mount, you will have to remove that RF shield which may require soldering.
If you are lucky, you will just unscrew the original lens (chip away the glue holding it in focus first, then install the new lens and see if you can get it in focus. If it focuses only with you holding the lens in front of the mount, you will need to modify the mount. If it focuses at least 1mm in front of the mount, you may be able to use an extender tube.
Good luck.

@TonyM is an engineer and photographer who has extensive experience and expertise modifying various types of dash cams with alternative lenses going back some five years or more here on DCT, including his popular thread Mobius Telephoto Dashcam. I seriously doubt that he needs novitiate advice from members with little or no experience in such endeavors. (His last two posts are merely further evidence of that.)

 
@TonyM is an engineer and photographer who has extensive experience and expertise modifying various types of dash cams with alternative lenses going back some five years or more
Rummaging around in the spare parts box... :)
PXL_20221029_192911060-01.jpeg
 
I have a similar looking collection! :happy: (plus lots of other spare parts extracted from older cameras)
Oh, don't tempt me! I'm sure I have a nasty frankenstein conversion in a drawer or box somewhere, alongside 5 or more defunct Mobii.
 
Oh, don't tempt me! I'm sure I have a nasty frankenstein conversion in a drawer or box somewhere, alongside 5 or more defunct Mobii.
Same here, including boxes of old Mobius parts and housings, plus cams like the M2. Mobius cams ship with such high quality lenses and their unique lens holders with grub screws so the last thing I would do is dispose of them.
 
If you are lucky, you will just unscrew the original lens (chip away the glue holding it in focus first, then install the new lens and see if you can get it in focus.

Probably won't focus without a mount extender to add some thread, the lenses on these cylinder shape rear Viofo cameras are a closer focus than the front camera lenses.
Thanks for the suggestions. Actually I had no problem installing the 6mm lens - it screwed into the holder by at least 5 or 6 turns before reaching focus.

PXL_20221030_114704045-01.jpeg

I will share my findings in a separate discussion thread. Initial tests suggest this camera unit could be an interesting base for alternative lenses. I assume that the rear camera (different sensor, no IR lamps) will be similar or even better, but more on that another time.

PXL_20221030_115801839-01.jpeg
 
Very curious to see the results with this lens/sensor combination.

For those who may not know what they are looking at, the 6mm lens Tony installed is a unique aspheric "Starlight" design with a fast ƒ/1.2 aperture. It can provide dramatically enhanced low light capabilities. When installed on a Mobius (1) camera for example, (not a camera known for outstanding low light performance), those of us who've experimented with it and its equivalent 4mm ƒ/1.2 sibling found that the camera often performed almost as if it had a different and improved sensor after dark as well as reduced motion blur during daylight hours due to faster shutter speeds.
 
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Now you just need to extend the windscreen mount a little!
 
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