Samsung ISOCELL HM3: 108 megapixel sensor with better autofocus and 12 bits
Samsung has installed a new camera sensor with 108 megapixels in the Galaxy S21 Ultra. Samsung not only offers the ISOCELL HM3 to its own smartphone division, but also to other manufacturers. The sensor offers a new autofocus that should work 50 percent more precisely. With HDR, the output should be in 12 bit.
At the presentation of the Galaxy S21 Ultra it was not yet clear which 108 megapixel sensor was used in the smartphone There was only talk of a new generation. With the announcement of the ISOCELL HM3, Samsung is shedding light on the darkness and also announcing that the sensor is in mass production. Samsung offers the sensors of its own smartphone division, but also other manufacturers. A well-known buyer of theprevious 108 megapixel generation is Xiaomi.
Super PD Plus for better autofocus
With the announcement of the 3rd generation 108 megapixel sensor, Samsung is responding to further changes than during the presentation of the smartphone. Super PD Plus, where 'PD' stands for the autofocus by phase comparison (phase detection), should improve the accuracy of the autofocus in the ISOCELL HM3 by 50 percent compared to the previous generation (ISOCELL HM2) by means of microlenses over the focus points in the sensor. Moving objects should be able to be captured more sharply, and Samsung also promises better performance under difficult lighting conditions.
Smart ISO Pro should generate 12-bit HDR recordings
Integrated at the sensor levelthe ISOCELL HM3 has a new HDR mode called Smart ISO Pro. Smart ISO Pro creates two images with different sensitivities (ISO) simultaneously instead of one after the other and combines them into a 12-bit HDR image. During the unpacked stream, Samsung spoke of two simultaneous 10-bit frames that are merged into a 12-bit recording, but without giving any details. The technology should no longer require staggered recordings and, above all, reduce motion blur. Smart ISO Pro should be used for recordings with different lighting conditions, for example at the end of a tunnel or when lighting from behind towards the camera.
Works under very good lighting conditions the sensor in the Galaxy S21 Ultra with the full resolution of 108 megapixels. Then all of the 108 million pixels are used for so-called “demosaicing” or “debayering”. In this process, the individual pixels that see red, green or blue using the Bayer matrix are assigned a color value using an algorithm by comparing each pixel with its two neighbors and determining the two missing colors. On the blog of the iOS camera app Halide the process is described with reference to Apple ProRAW . Samsung's new algorithm uses twice more for this processPixels than before.
12 instead of 108 megapixels in poor lighting conditions
In poor lighting conditions the sensor performs non-binning to combine nine pixels into one pixel. Instead of the normal edge length of 0.8 μm per pixel, this corresponds to a sensor with only 12 megapixels with an edge length of 2.4 μm per pixel. The ISOCELL HM3 supports the smooth change between 108 and 12 megapixels.
Ultimately, Samsung also wants to have reduced power consumption. In the preview mode with the viewfinder activated, this was reduced by 6.5 percent.