This photograph of Buzz Aldrin was taken by Armstrong
on the moon's surface.
The camera he was carrying
was mounted on his chest pack. So why does the picture appear to
have been taken from above Aldrin and we can see the top of his head?
The answer to this question is quite straight-forward. The ground they are standing on is not flat. Armstrong was further up an incline, so he was higher than Aldrin.
A really interesting series
of photos with commentary by Buzz Aldrin himself.