I can often tell when drawings are done from photographs, because you can tell what they miss out, what the camera misses out: usually weight and volume - there's a flatness to them.
David HockneyPhotography hankers after the condition of the neutral observer. But there can be no such things as a neutral observer. For something to be seen, it must be looked at by somebody, and any true and real depiction must be an account of the experience of that looking.
David Hockney