In the lawsuit, Jason M. Allen asks a Colorado federal court to reverse the Copyright Office’s decision on his artwork Theatre D’opera Spatialbecause it was an expression of his creativity.
Reuters says the Copyright Office refused to comment on the case while Allen in a statement complains that the office’s decision “put me in a terrible position, with no recourse against others who are blatantly and repeatedly stealing my work.”
It's human expression that is protected by copyright. Creative height is the bar.
If you've done nothing but press a button there's often no copyright. Photography involves things like selection of motive, framing, etc. If you just photograph a motive which itself doesn't have copyright, then what you added through your choices is what you may have copyright of. Using another's scan of a public domain book might be considered fair use, for example (not much extra expression added by just scanning)
Independent creation is indeed a thing in copyright law. Multiple people photographing the same sunset won't infringe each other's copyright, at least not if you don't intentionally try to copy another's expression, like actively replicating their framing and edits and more.