A118C with GoPro 3 lens MOD

Adriano

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Hi there,

I wasn't very happy with the stock lens so i went online and bought from aliexpress a gopro lens.
It costs ~20 USD and it-s plug and play,just unscrew the original and install it with no modifications.

First you have to know that the gopro lens has a ~153 degree FOV and it's slightly less smaller in diameter,about 1mm it's not noticeble nor it stands out of the housing.
I'll post some pictures,right now i'm testing it and from the firsts shots i think it has a wider apperture as with default EV image is brighter but much more detail and the noise is not that noticeble with the march 18 FW.
I'll make a small compilation this weekend,patience.

Lens was bought from here
 
That's an interesting find, looking forward to seeing your compilation with the new lens. Was it as easy to install as you seem to suggest?
 
That's an interesting find, looking forward to seeing your compilation with the new lens. Was it as easy to install as you seem to suggest?

you need to open the camera up etc but the lenses are a standard screw thread, out with the old, in with the new
 
Yes,it's same thread,just unscrew and install the new one.
I have to reposition the lens and sensor in the housing as i can see that it doesn't sit perfectly horizontal,lost the screws and used hotglue instead.
Lens installed:
IMG_20150531_182910387_HDR.jpg IMG_20150531_183013812_HDR.jpg
And a small daytime footage with EV set to -1/3.Soon i'll post a nightime video,i'm curious if it's a noticeble difference.
 
Lens was bought from here
Another question is that lens original GoPro lens and does it provide similar video quality as the original Hero 3?
No point replacing the stock lens on A118 if this is a fake lens giving inferior video quality.
 
Another question is that lens original GoPro lens and does it provide similar video quality as the original Hero 3?
No point replacing the stock lens on A118 if this is a fake lens giving inferior video quality.

they just call them GoPro lenses, it's not the same lens GoPro use
 
they just call them GoPro lenses, it's not the same lens GoPro use
I thought so. Then the next question will be is the image quality as good as genuine GoPro lens or better than stock A118 lens?
 
GoPro do use a good good lens, unlikely you're going to find one of the same quality on aliexpress or similar, it may be better than the one on the A118 but still might deliver mixed results depending on firmware and how much that lens differs from the stock one
 
All dash cam lenses are industry standard M12 thread x .05 pitch also known as "S" mount board lenses. The aftermarket "GoPro" lens used here is probably better than the stock A-118 lens but is not of the same quality as an actual GoPro lens. It is a nice stroke of luck that it worked so well in this camera. Even though the threads are the same, often the lens barrel and threads are longer or shorter than the stock lens and it won't work. Usually, it's related to the back focal length (BFL) of the lens and the ability to focus onto the image sensor in the camera in relation to where it is screwed into the lens mount. Another related issue is the circle of coverage each lens can throw. The lens mount on the GoPro is very long so if the threads of the lens are too short, or the BFL doesn't match up well with the sensor the lens will never focus. It is even possible to damage a sensor in a camera with an aftermarket long threaded lens because you can accidentally screw it in too far and damage the sensor while trying to get it to focus. Also, as jokiin points out the camera's firmware needs to be optimized for each lens. The sample footage here looks good!
 
I made a day and night video with my A118C,looks pretty good i'm gonna leave it like this but i'm still looking for a solution to install a CPL filter.
 
Any tips on how to re-focus the GoPro lens after installation? Is it going to be as tedious as I think... plug it in... test-record a few seconds... pull out SDcard... inspect for focus on a computer... turn lens in/out to focus some more... repeat... repeat, etc.

I assume the LCD screen is too low-res and small to check for focus. Thanks.
 
Google image search "focus chart"
Use that at the distance you want. That should be good enough to see on the small screen for starters and you can go from there.
 
Any tips on how to re-focus the GoPro lens after installation? Is it going to be as tedious as I think... plug it in... test-record a few seconds... pull out SDcard... inspect for focus on a computer... turn lens in/out to focus some more... repeat... repeat, etc.

I assume the LCD screen is too low-res and small to check for focus. Thanks.

The A118C has an AV out port which should allow you to connect it to an HDTV for focusing. However, that will depend on whether the AV out will provide a live image view and I'm not certain it will do that, so you would need to confirm. If it does it will be much easier to focus than if using the little on-board screen.
 
The A118C has an AV out port which should allow you to connect it to an HDTV for focusing. However, that will depend on whether the AV out will provide a live image view and I'm not certain it will do that, so you would need to confirm.
gives a live image but it's downscaled to SD, not very clear
 
My A118Cs' lens scratched. Can I replace with this:
 
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