Ive been doing that for years
but when I want a different look I like to use Poser for the render..
I cant figure out why this happens with the Bryce rendered files
I have a moonpic Ive dowloaded somewhere and that works fine no distortion in the edges
I post it here and youll see the differens
inyerface ...yours are better but if you look closely you have a distortion around the edges also