GSM Arena has a good summary:
The massive Samsung GN2 sensor makes its debut with the Mi 11 Ultra. At 1/1.12” it is the largest sensor ever used in a mass market phone and it has some of the largest pixels we’ve seen in recent years – 1.4µm before anyone even mentions the word “binning”. The GN2 does in fact support 4-in-1 binning that makes the effective pixel size 2.8µm.
The sensor enjoys the benefits of Optical Image Stabilization (OIS) and introduces Dual Pixel Pro, which improves autofocus speed and accuracy. There’s also Smart ISO Pro, which can capture HDR photos in an instant.
The two other cameras on the Mi 11 Ultra’s back are no less impressive. The periscope lens offers 5x optical and 10x hybrid zoom. Even better, it is paired with a 48MP sensor (IMX586), which is fairly large in its own right – 1/2.0”, 0.8µm pixels (1.4 µm after binning).
Next up is the ultrawide camera, which has a 128° lens and a 48MP 1/2.0” sensor of its own (IMX586 again). The lens has autofocus and can shoot macro photos. Like the other two cameras on the back, this one can record 8K video. Also, all three have Night mode support.
In terms of other specs, you'll be interested in the 67W Qi wireless charging support, filling the battery in just 36 minutes. Given that we started with 5W Qi charging on the Lumia 920 and that 15W is still considered the maximum on many other 2020/2021 smartphones, this is all very interesting from a physics point of view. Anyone care to predict how hot this will get when wirelessly charging at 67W?(!)
- a 6.81” AMOLED 120Hz HDR10+ display at QHD resolution, with Gorilla Glass Victus protection.
- a Snapdragon 888 chipset with 12GB of LPDDR5 RAM plus 256GB of UFS 3.1 storage.
- stereo speakers that were 'touched up' by Harman Kardon.
- IP68 waterproofing.
- a secondary 1.1" AMOLED panel on the back, for notifications and selfie framing.
In Europe, the 12GB/256GB model will be available "soon for €1,200". So possibly £1100 inc VAT in the UK. Which, given the spec, is possibly justified this time around, even though I can't personally spare the cash 8-)