The first generation of under-display cameras (UDC), like the one on the ZTE Axon phone line, are a rather weak sauce when it comes to image clarity and color quality output. ZTE promised that the second generation on the upcoming ZTE Axon 30 will have none of it, but now Oppo has unveiled UDC technology it directly claims as second generation, too.
Oppo uses AI to compensate for any remaining diffractions, it says, and the whole display is able to seem uninterrupted by the UDC area no matter the content shown, due to proprietary per-pixel chromaticity and brightness management. The result? well, selfies like the one you see below that is very close in quality to one from a regular exposed selfie camera.
Second-gen under-display selfie camera quality” 
Moreover, ZTE says that it uses a 16MP camera with tiny pixels and 4-in-1 pixel binning to achieve 2.2 micron “equivalent” pixel size. Given that the Galaxy Z Fold 3 is said to arrive with a 4MP under-panel camera (that’s Samsung’s term for it) we can’t help but think that it swapped a relatively unimpressive resolution for a sensor with a big non-virtual pixel size.
Galaxy Z Fold 3’s under-display camera
