Preliminary reports hint at the Galaxy S11 series adopting a 108-megapixel main camera, namely the ISOCELL Bright HMX which was developed in collaboration with Xiaomi. However, the Galaxy S11+ (at least) could sport an ‘exclusive custom' 108MP sensor that has a higher production cost. Presumably, this would be a spin-off of the existing 108MP solution, but one that would provide some extra benefits.
The higher cost is attributed to superior quality compared to the ISOCELL Bright HMX sensor, at least according to @UniverseIce. It's not entirely clear how this alleged custom camera model would be better than the unit employed by Xiaomi's newer smartphones, but the source claims that it will have the same sensor size of 1/1.3 inches.
The Galaxy S11+ uses a 1 / 1.3-inch 108MP Samsung exclusive custom sensor, which is superior in quality to ISOCELL Bright HMX and has a high cost.
— Ice universe (@UniverseIce) December 8, 2019
The ongoing ISOCELL Bright HMX was unveiled roughly four months ago, and while Samsung has yet to equip it on any of its smartphones, Xiaomi already uses it for the Mi CC9 Pro and Mi Note 10. The Chinese company will continue to adopt the sensor for other models expected to hit the shelves soon.
It would make some sense for Samsung to want and differentiate the flagship-grade camera of its own smartphones from those developed for its competitors, or indeed its clients. And if the report is correct then this ‘custom' sensor based on the ISOCELL Bright HMX will remain exclusive to Samsung's product lineup.
Whether or not this will be the case remains to be seen, but as usual, it's not a bad idea to be a bit skeptical of unconfirmed rumors. Either way, the Galaxy S11 rumor mill isn't going to stop spinning anytime soon so we'll keep you updated with new details as they surface.