Re: 108 Mpix?!
To quote the official page:
https://news.samsung.com/global/introducing-the-samsung-galaxy-s20-change-the-way-you-experience-the-world
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With a larger image sensor available on the Galaxy S20 series, camera resolution is significantly increased [...] S20 and S20+ have a 64MP camera. S20 Ultra has 108MP camera [and] takes things a step further with the option to shift dynamically between a high resolution 108MP mode and a 12MP mode, thanks to nona-binning technology which combines nine pixels into one at the sensor level
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I.e. you only get the 108MP lens on the Ultra, but if you do, you can choose to shoot full-resolution photos if that's your thing. Personally, I think I'd stick with the downsampled images!
Presumably, this also means that you don't get the 9-pixel binning technique on the S20 and S20+, given that they've got a 64MP lens and hence would spit out a ~7MP photo if this was enabled.
As ever, I guess we'll just have to wait and see what the reviews say!