system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can't phones be able to shoot landscape photos while being held vertically? Alot of people are complaining about videos being shot in portrait mode, don't phone companies take this into consideration?
gpt
Some phones record video properly no matter how you hold them, but shoot photos in both landscape and portrait modes.  

Photo sensors aren't square.  They are rectangle.  If you shoot landscape mode (wide) against a sensor oriented for portrait (tall), you would only be using a very small portion of the sensor which means that you would get a much lower resolution.  

Since video shoots at a lower resolution, using just a portion of your sensor wouldn't be a big deal until you tried shooting in low light situations.