Why YSK: I’ve been seeing an increasing number of phone photos shared online in 9:16, 9:21 or similarly tall aspect ratios, often with parts of the subject cut off. I’ve asked a few people why they cropped their images that way, and none of them knew they were cropped.
I did some testing on my phone, Samsung S22, and it looks like 1:1 uses the most of the sensor. Any other aspect ratio was zooming in. This is particularly upsetting to me since I was using the “full” setting which cropped the most but I thought I was using the most of the sensor.