For years, smartphone makers raced to include the most megapixels possible in their cameras, but more pixels doesn’t guarantee a good camera. After a brief respite, manufacturers are again trying to cram in more pixels. Devices like the Samsung Galaxy S20 Ultra and Motorola Edge+ have a 108MP primary sensor. Samsung’s latest ISOCELL GN1 sensor has fewer pixels, but it might take better photos thanks to improved autofocus and bigger pixels.
Like many aspects of the modern smartphone, camera performance is constrained by the size of the device. These camera sensors are small compared with what you can fit in a “real” camera. Cramming in more megapixels means each pixel on the sensor gets smaller and less sensitive to light. The megapixel race picked up again when manufacturers developed pixel binning technology that can rope together several smaller pixels to act like one larger pixel. So, your phone might have a 108MP sensor, but the photos are only 12MP.
The ISOCELL GN1 has 1.2μm pixels, which is on the large side for smartphones. It also supports Samsung’s Tetracell pixel-binning technology to produce larger effective pixels (2.4μm) and collect more light. Samsung says this doubles the sensor’s light sensitivity and produces 12.5MP photos.
Samsung launched the S20 Ultra earlier this year with the 108MP ISOCELL Bright HM1. While this sensor is more technically capable than the GN1, it hasn’t performed as well in practice as we’d hoped. The S20 Ultra was almost universally derided for sluggish autofocus, which used phase detect technology. With phase-detect, light splits upon entering the camera. The lens elements adjust to merge the two images, which means they’re in focus. This is harder to do with larger sensors, though.
The S20 Ultra’s giant camera assembly, courtesy of iFixit.
The ISOCELL GN1 should improve focus performance with the use of Dual Pixel autofocus. Dual Pixel technology analyzes each diode’s signal to determine focus and then combines those signals to create a sharp image. Dual Pixel technology specifically means there are two photodiodes in each pixel, for a total of 100 million phase-detection auto-focus (PDAF) agents.
The ISOCELL GN1 will go into mass production later this month, so it could appear in phones over the summer. Some will be from Samsung, but many won’t. While the GN1 sounds like a good alternative to the 108MP HM1, Samsung probably isn’t done trying to fix that sensor. We expect to see the HM1 make a return in the Galaxy Note 20.
