why not just have larger photodiode to increase dynamic range? can't see how using more photodiode would equal more dynamic range or better noise levels? never seen a sony,canon etc get less noisy and better dynamic range as they add more mega pixels..
The iPhone is using a quad-bayer filter. Most of the time, it is behaving as a 12MP camera with error correcting photodiodes.
Compared to a normal 12MP camera, the 48MP one will collect slightly less light due to there being more gaps, but the bet is that the increased noise from that is less than the noise reduction from the pixel-binning.
Every photodiode has three others around it with the same colour. If they’re all similar, the sensor will average them, and if one of them is way off, it’ll throw that one away and average the rest.
This is better than doing noise reduction on either a 12MP, or a standard 48MP sensor because the space between comparable diodes is reduced, making it less likely to falsely treat small things like stars as noise.
As a bonus, if the user zooms in on a really sunny day, the 48MP might actually be worth using directly.
