Over the course of the semester, we have read stories and then watched films based on those stories. The basic idea behind a story is usually kept in its film adaptation; however, certain points or details may be omitted for the sake of viewing time. It is the amount of omitted information that separates a good adaptation from a poor one. The less information omitted, the better it tends to be in the eyes of those who have read the original work.
The film which best captures the essence of its source material is the film version of George Cukor's 1964 My Fair Lady. Everything in the text happens in the film, from the dialogue to the songs. Even though it is based on George Bernard Shaw's 1913 play, Pygmalion;, however, it is its own story. The fact that there are major differences--such as the locations and the ending--makes My Fair Lady a story unto itself, and this story makes a perfect word-for-word transition to film.
On the other hand, one of the films we watched omits so much detail that if the audience had not been told, they would never guess that it were based on a novel. Luis Buñuel's 1954 Los Abismos de Pasión is based on Emily Brontë's 1847 novel, Wuthering Heights; and while the basic theme of love and revenge is kept, the film adds and omits several details to make it unlike the original story. The scene during the characters' childhood is only mentioned, never shown in the film. I think that bit was important because it develops sympathy for Heathcliff/Alejandro (Jorge Mistral) and explains his later actions.
Information is omitted in this film, but the film makers also add a few things. Most importantly, they add a touch of vampirism into the story with Alejandro's seduction of Isabel (Lilia Prado). He constantly kisses her neck; and, as he continues, she fights back less. Also, when Alejandro goes to the grave of Catalina (Irasema Dilián), he kisses her, as if trying to awaken her. All of this helps make the story original, but not entirely Wuthering Heights.
I am not saying that either of these films is better or worse as films go. However, in terms of faithfulness to source material, they are both in separate categories. Whether someone likes or dislikes a film often depends on his or her point of view on how the movie is conducted and whether he or she likes a story. As for me, this is my standing.