We're already seeing 48Mp camera phones introduced into Xiaomi's line-up, currently featuring in the top-end Mi 9, Mi 9 SE and Mi 9T, as well as cheaper models such as the Redmi Note 7 and incoming (currently Europe-only) Mi A3. Very soon we could also see 64Mp cameras in upcoming models.
Samsung announced its 64Mp ISOCELL Bright GW1 sensor at the beginning of May, which uses Tetracell binding to combine four pixels into one, resulting in a much higher-quality 16Mp image - especially in low light.
The new sensor can also enable enhanced phase-detection autofocus, real-time HDR and Full-HD video at 480fps.
In July Xiaomi posted a camera sample to Weibo that was captured on an upcoming Redmi phone with this sensor, suggesting that such a device is imminent. It is not clear yet as to which Redmi model will use the new camera sensor, though we can almost certainly expect it to also appear in 2020 flagships such as the Mi 10.
The company then demoed the technology at its Xiaomi Future Image Technology Communication Conference on 7 August - just beating Realme to the punch, which demoed the same technology the following day. We now know that this 64Mp Realme phone is the XT, and it is arriving in October.
The GW1 sensor is larger than those we've seen on previous Xiaomi phones, with a 1/1.7in CMOS sensor, yet maintains the 0.8um pixel size of the current 38Mp sensor. The 9248x6936-pixel resolution of this sensor is able to create photos that are 38% larger than previously - up to 244x326cm - though you'll get better quality when combining those pixels into one 16Mp image through pixel binning.
Xiaomi also teased an unknown Samsung sensor that can capture 108Mp (12032x9024) stills, which will be used in a future Mi phone.