It's just the former.

Another way to see things. Let's say you sit in your couch and look straight in front of you without moving your head. The perspective is given by the relative distance between the objects you see.

By moving your head to the left and to the right, this perspective does not change (or just a tiny bit because of the head movement ) but you see more of the things that surround you. You are increasing your field of view by rotating your head and the same is achieved by mounting a lens with short focal length vs. long focal length. Otherwise, your perception of the volumes surrounding does not change.

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frame4zoom for Nikonians