Just how much of a noticeable difference or improvement is there on this unit over the A139 rear cam?
The rear camera appears to have the same body as the A139, although I haven't put them side by side to check, I currently have mine stuck to different windows and they are not demountable.
The lens is very similar, they use a smaller size lens than the front cameras, just to keep the cameras small and easy to install.
So the difference is mainly in the sensor, we have an IMX335 instead of an, is it a IMX291 or a IMX307? I think it is an IMX291 in the A139?
So it is the same difference as the front camera in the A119 V3 vs A129, or A129 vs A129 Plus.
Essentially twice the detail and a slight loss in dynamic range. This means that you can read a number plate at about 50% further distance, and if you are trying to read plates in the next lane then about a 50% reduction in motion blur when they are at their best point. You will only really notice these differences with a side by side comparison, something I've not done yet with the rear cameras...
Of course if you are only trying to read the plate of the car behind you then there is probably no need for 2K resolution, but I seem to use my rear camera more for vehicles in other lanes than I do for the vehicle behind. Often it is a vehicle going in the other direction that I am interested in because the front camera didn't catch the plate for some reason, maybe lighting conditions, or maybe I was in a car park and the other vehicle came from the side, so was not seen on the front cam but was captured leaving the scene by the rear camera.
The A229 very clearly has the better rear camera, but it is mainly a question of detail when you look at the images closely.
One other note, the A229 rear camera is sometimes a little low on bitrate, which also reduces the quality compared to the front cameras. Normally this is not an issue, especially if you have a car behind you with smooth surfaces rather than lots of trees with a vast amount of detail, but the 2K image should require twice the bitrate to actually give twice the detail, and it doesn't have twice the bitrate of the A139 rear camera, so while you will normally see twice the detail, if driving fast under trees, the quality may be reduced, and I do recommend setting maximum bitrate if you want full detail.