It is short-sighted to judge the film adaption of a novel by the same criteria as the original text. I get really annoyed when I hear a movie being criticised for 'leaving out' parts of the book; if a literal adaptation of a novel was ever attempted, it would be an extremely tedious and dull experience for the viewer, not to mention the longest film ever made. The director's job when making a screen version of a written work is to put across the essence of the story, using the elements of the book that are most relevant to the visual medium. With some books this task is quite simple. For example, Cormac McCarthy's novels read very much like screenplays and embody a cinematic tone, meaning that the film adaptations of No Country For Old Men (2007) and The Road (2009) easily retain the qualities that made the books so enjoyable. With longer fantasy-based novel's like Harry Potter, the director's retelling has to be much more subjective.
This leads me onto my next point: the role of a film adaptation isn't to provide a carbon copy of the original. Like it or not, but the director has a duty to present their own interpretation of the story, not just regurgitate the author's views and sentiments. When Katsuhiro Otomo adapted his own manga classic Akira (1988) to the screen, he made drastic alterations to the narrative, presenting the version of his story that works best for film. I will admit that I haven't always agreed with the choices a director/screenwriter has made during the adaptive process, but I'll defend to the death their right to make those choices. In a way, the activity of adapting a novel to the screen is just a continuation of the tradition of oral storytelling. As the narrative is passed on by one teller to the next, it is warped and contorted, gradually leaving behind many of the elements that made up its original form. In this case the director becomes just another link in the storytelling chain, passing on their version of the tale.
Don't get me wrong however; I'm not saying that cinematic retellings of novels should replace the original written document. Both are equally valid versions of the story, as long as they told with skill, imagination and integrity. Although I don't like people automatically attacking an adaptation movie, I also detest it when someone states that they won't read a book because they can just watch the film version. This attitude ignores the fact that all films start out as a written document; a screenplay. Without reading, and the imaginative processes it generates, there wouldn't be any films.
There is one situation where I do oppose the adaptation of books into films, and that is when 'Hollywood' gets involved. By this I mean, when studio execs look at a literature masterpiece and only see dollar signs. When this happens all the truth of a text is lost, replaced with the shallow goal of generating the biggest box office success. My example for this phenomenon would be I Am Legend (2007). Richard Matherson's original novel is a horror classic, chilling and inventive, with a really powerful if bleak conclusion. Director Francis Lawrence's adaptation removes almost all of the tension, replacing it with off-the-shelf jumps and scares, and reduces the vampires (yes, they are vampires, not weird zombie things) to unrealistic CGI ghouls. And the altered ending; don't get me started! Without wanting to spoil the story, the film's conclusion has no meaning at all, it says nothing new. But who cares when the film took $585 million worldwide? Isn't that what filmmaking is really about? I'm not so sure.
So in conclusion: not all novel-to-film adaptations are bad, in fact some books feel like they were written to be converted. I think I'm right in saying that Chuck Palahnuik actually acknowledged that he considers David Fincher's version of Fight Club (1999) to be superior to his novel. However, that doesn't mean that reading should now be obsolete; film cannot exist without the written word. I'll let you know what my assessment of the latest Potter adaptation in the not-too-distant future. In the meantime, keep reading AND watching!