Movies based on books are a whole different genre. Since they are inspired from books, they should be true to the original material in terms of details and the plot. But most of the times they aren't. Harry Potter series is the only one that comes to mind that stuck faithfully to the original.
It took me a while to reconcile why the movies based on books are different from the original. I still don't agree with changing fundamental details of the plot (Like the ending of The Idea of You was changed in the film) but I can see why some things are changed. First of all, books and movies are two different genres and are perceived differently. The story, while great in essence and idea, may not translate exactly on screen to be entertaining. We expect different things from a book and a movie. We are in different frames of mind when we consume each form of media. And I think that is one of the main reasons why books cannot be translated exactly on screen.
Also, books are better for story and character development because they are not restricted in scope, mostly. While all books are not War and Peace length books, most have the freedom to be long enough to sufficiently go into the background of the story. To paint a picture and describe feelings. To take us on an imaginary joyride with as many pages as it takes to do that. Movies have time limit and hence it's hard for them to be as rich and detailed as books. Plus, like I said, movies don't have the luxury to spend time backgrounds etc. The makers have to be clever about which parts of the story to take while keeping the audience interested and how to cleverly introduce parts of the book so that we know what motivates the characters to do what they do.
I am not sure about this but another reason why books don't convert loyally to movies could be copyright issues. Most books are said to be based on or inspired from to relinquish any claim of copying some author's work. Like when they change dialogues or how the scene goes on screen compared to the book. I don't know if that's creative liberty or the fact that they don't want authors claiming that their work was copied.
The parts of the story are chosen based on what might become an interesting film worth watching. For instance, Red, White And Royal Blue, as a book is quite long. It. has a whole romantic track and whole political track. The book on screen would be double the duration that it is now. Maybe longer. However, in the interest of keeping it more interesting, the makers have picked up the romantic track and left out most of the political part of the book. The story of 2 men in love - that too 2 powerful men who are famous across the world - is a great plot for a movie. While the book has a lot of additional characters to build a wholesome fictional world, the movie does not have that scope and liberty.
My biggest gripe is when they change the story beyond recognition - for example Confessions of a Shopaholic. Had this been even remotely faithful to the book, I'd watch it over and over again. And this franchise of movies could have the potential of becoming classic movies that brought in the moolah too. But the first one is so badly made that I am glad and not surprised that no one made more movies in the shopaholic series. The makers should be sued for even suing the same title.
The reason why I thought of this topic is because I watched the film, It ends with us, today. I wrote the book review a few days ago. While the book is great and has all the time to follow the train of thought of a victim of domestic abuse, the movie is slow and not as impactful. If someone hasn't read they book, they may have a hard time connecting some dots.
In fact it probably has about 40% of the original material. The pace is slow and the depth of the book is missing. There is whole build up the abuse and the separation in the book. there are solid reasons why she chooses to ask for a divorce. even though the pace is slow, not enough time is spent in the film on that build up. Atlas is introduced too soon. The book has fantastic one liners about how relationships change in seconds. The movie is missing that connect.
When there is a book and a movie, I choose to read the book first. And since I understand that the 2 genres are different and that's why I can digest the ending of The Idea of You. While the book ends with Hayes and Selene breaking up, the movies goes 5 years forward and reunites them. They have also changed the age of the characters to better translate it on screen.
There are also times when I came across the movie/series before I read the book or knew it was based on a book. I have realised that going back to read the book doesn't really work. I tried to so that for The Devil Wears Prada and Chesapeake Shores. the parts of the book that are not in the movie seems jarring. It feels like the book isn't doing justice to the film although it is not supposed to. But the human mind is an interesting thing. We can't un-see/unread what we already know and that becomes the primary material in the mind.
What do you prefer to do - read a book or just watch the movie instead? How do you reconcile the changes that happen when one is translated into the other? Do you have any favourites?