I remember this bit in Christopher Isherwood's essay about RL Stevenson's travels with a donkey. he said - you can't help wishing you were doing the journey with DH Lawrence instead.

This is all a bit like that. the imagination of the film maker is not REALLY what your imagination has furnished you with from reading the book.

somehow when a film maker adds lyricism - like in the Godfather - those pictures -so dark , they almost seemed like composed paintings. his vision, rather than your own or the authors, literally sweeps you away.