Problem i found with the rear cameras i had so far.
1. The ordinary wide angle lens make it hard to see as the car behind appear to be further away than it actually is.
2. often the sky reflect in the windscreen of the car behind, making it hard to see in the footage what is going on, i am not sure if a CPL filter would help with this issue.
3. i have tried larger lenses ( up to a 15 mm ) and that help a lot with getting up close with the person in the car back there, but that in turn make the FOV smaller and so i have tried to think " got ya" in the car, but reviewing the footage at home the person is not in frame.
I actually think with if using a narrow FOV lens it might be better to put it to the side of the rear window and not in the mittle, but still thats a issue as the car behind dont allways follow dead in your tracks, so the offset will place what you like to capture out of frame.
IRL what you see the most in regard to ppl texting while driving or stopped at intersections, is they look down into ther lap and can only be doing 1 of 2 things.
A. play with them self
B. be texting/on the phone
At night the glow of the screen will give them avay.
I have dropped capturing phone junkies with my rear camera, but my side cameras do pretty good, so much so i wish i had one in the Left side of my car too.
Side cameras do however present another problem, there is no wipers there so water will bead on them, so some form of nano stuff on those windows is preferred, and offcourse cleaning your car more often that i do will help a lot too
The 90 deg lens on the innovv C3 i have in the side is perfect, but the C3 have some issues of its own so its not the 100% perfect side camera.
I have tried the C3 lens on my rear mobius, that worked too.
Dashcams and ther lens is often a optimised bunch of components, but that dosent mean that putting on another lens will make the footage useless, but offcourse you have to stick to good lenses and not the cheapo 2 doller ones you can fine on the interweb.
I really wish some one would sell other lenses, i would buy a handfull thats for sure.