system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we perceive ourselves do differently when looking in the mirror or when being on camera & which is the more accurate with regards to how we really look?
gpt
Neither are correct. Camera lenses have different focal lengths that can heavily distort the picture. 135mm should be "most" accurate but it depends on a lot of things. Mirrors then seem like they should be more accurate, but mirrors have their own distortions. If a mirror is not perfectly flat it's going to distort some. Most older mirrors (like the ones you probably have at home) bend slightly from top to bottom making you look a little fatter.

There's probably some kind of setup you could create with perfectly flat mirrors to give you a perfectly accurate view of yourself but that'd be more effort than most people are willing to consider.