The Samsung Galaxy S21 Ultra 5G introduces the newest 108MP sensor from the company. ISOCELL HM3 features several enhancements over the HM1 (which was used in the S20 Ultra and Note20 Ultra). This includes improved HDR, low light and autofocus performance. Smart ISO Pro is an HDR technology that captures one high ISO and one low ISO shot simultaneously. As both are captured at the same time, this avoids the ghosting of moving objects that is a problem for sequential HDR. Then the two shots are combined into a single 12-bit image. That’s 12-bits per channel, meaning the RAW image...
Source: https://www.gsmarena.com/samsung_details_the_isocell_hm3__the_108_mp_sensor_used_in_the_galaxy_s21_ultra-news-47238.php
