Perspective distortion

The distance to camera distance can make your picture have "distortion". It's more noticeable on a wide focal length and are there for often confused with that it's the focal length that makes the distortion.

A persons nose in a fish-eye lens will lock very big in comparison to he's/her ear that are further away

Also then the focal plane and the subject not perpendicular you get distortions, when taking a picture of a building standing on the ground. The buildings top will be smaller than it's base. This can be fixed by a perspective control lens