The Galaxy S9 and S9+ use different camera sensors in some markets

The S5K2L3 is an upgraded version of the S5K2L2 sensor that powered the main cameras in the Galaxy S8, S8+, and Note 8, while the IMX345 is similar to the IMX400 that debuted in the Xperia XZs last year. Both have a 3-layer design that consists of a CMOS image sensor, an image signal processor (ISP), and a DRAM chip for buffering 960fps ultra-slow mo videos. The difference is that the IMX chip puts the DRAM between the ISP and the CMOS sensor, while the ISOCELL has the CMOS and ISP wafers conventionally bonded face-to-face, with the DRAM connected to the ISP face-to-back.