I'm really sure you have an IP lawyer on retainer..

Although, you are probably right in the circumstances discussed above, however, what about something like this:

you take an artistic photo of posters on a building wall in a city street. It's your photograph of a real place, but conaints images that are probably copyrighted..what's the answer here, are you infringing on the indivudual copyrights?

This seems absurd, because it then limits what part of the world an artist (or anyone) can document/represent.

The same argument can be extended I think, to a more general case.