https://www.youtube.com/watch?v=rIhK1hY1–Q
Although the Galaxy S21 Ultra has an IP rating and can be submerged underwater, attempting to do so in a marine environment would almost certainly ruin it due to the high atmospheric pressure and salinity. That's why the smartphone is encased by a protective layer. That could, in theory, affect the quality of images because it adds an extra layer for light to refract through. That doesn't seem to have bothered the Galaxy S21 Ultra a whole lot, as it still managed to capture some stunning images of the ocean.
Our Galaxy S21 Ultra review determined that the quality of 8K videos recorded by the smartphone's camera is only marginally better than the ones shot at 4K. Perhaps National Geographic has better use for 8K footage than the average consumer, given that they are used to shooting at the resolution all the time with their standard equipment.
