Samsung just introduced its 50MP Isocell GN2 sensor, the successor to the GN1 launched last year. The GN2 is a large 1/1.2-inch sensor with big
1.4μm-sized pixels and claims improvements in AF speeds, Smart ISO control, and is the first Samsung sensor to integrate Dual-pixel Pro PDAF.
The sensor can capture 100MP resolution images using a re-mosaic algorithm, and that should perhaps help with better marketing and with the GN2 ending up in more phones than the Isocell GN1.
As for videos, there is support for 4K@120fps and Full HD+ videos at 480fps.
What is Dual-pixel Pro Phase Detection Auto-focus technology?
Basic PDAF or phase Detect Auto Focus technology works using special focus pixels embedded within the sensor. These focus pixels are split in two halves and use the same technique as our two eyes for focusing on image subjects. The lens is adjusted till the images or light captured by the two halves (left and right) merges into one or is in the same phase.
Dual-pixel Auto Focus enhances this technology further by slitting photodiode under every pixel into two halves, thus eliminating the need for separate focus pixels and improving focus speeds.
Dual Pixel Pro AF with photodiodes under green pixels split diagonally 
With Dual Pixel Pro, the photo diodes under Green pixels are split diagonally instead of vertically and this enables then to compare and align both right-left and top-bottom part of images, thus improving focus speeds, especially for complex images where it’s hard to tell left and right phases apart.
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Sony claims similar PDAF enhancements with its 2×2 OCL (On-chip lens) technology that allows every imaging pixel on its IMX sensors to serve as focus pixel and to measure phase horizontal and vertical phase differences.
What is Staggered HDR?
Samsung GN2 also supports staggered HDR that Qualcomm started supporting with its Spectra 580 ISP used in Snapdragon 888. This is not the first Samsung sensor to support Staggered HDR, that would be 32MP Isocell JD1 designed for selfies.
The staggered HDR sensors can capture three images with long, medium, and short exposures (or at different shutter speeds using rolling shutters) in the same time when normal sensors capture one image. This helps capture better details in highlights and shadow regions while reducing artifacts.
Samsung claims that staggered HDR also helps reduce power consumption of the Samsung GN2 sensor by 24 percent. It doesn’t mention whether stagggered HDR will be supported for Videos and at what FPS.
