How do I permanently disable Auto Portrait mode on my iPhone?

Whenever I take a photo of a person, my phone camera will automatically take it in portrait mode. I don't have my phone set to portrait mode, and it doesn't do this with photos of non-people, so I assume it is an automatic setting that apple has added. I don't usually think to check before taking pictures because I am used to it not changing. Is there a way to permanently disable this feature?

[Re-Titled by Moderator]