Why are photos and videos always cropped on phone orientation? Isn't the lens proportional in width and height? Is there a specific reason they are cropped to the orientation?

Does AVFoundation have API that would let me take full uncropped photos and videos? I’ve read through some of the documentation but nothing that would help me achieve this stands out.
The sensor in an iPhone camera is not square, it is rectangular physically. 

Therefore, ‘uncropped’ is rectangular and square is a crop of this. If you would like a square photo, you can use the square function in the camera app, but this will be a lower resolution as it is just a crop of the original rectangular image.



https://en.wikipedia.org/wiki/Image_sensor_format