A big misconception among some movie viewers is that a film based on any type of literary property should be exactly as the book is written. The passion and love for a particular book is understandable, but it is not practical. A film and any kind of book each have two different methods of functionality and storytelling techniques to the human brain.
For example, a novel has to set a scene, a full range of emotions and all five senses by only using words. A quality book will be very descriptive throughout paragraphs, thus giving each individual reader their own concepts and visualizations of what is occurring. A film has only so much time and so many shots to use to move a story along. Only two senses are stimulated in a film; visual and audio. Sights and sounds in a film are pre-determined by the production staff.
The pacing of plot movement in a book can vary in depending on the priority of scene setting, emotion and dialogue. A book can range somewhere from 20,000 to maybe a 120,000 words. A film has on average 90 to 120 minutes of run-time and a screenplay is only 120 pages that are not written in paragraphs. Movies are considered as motion pictures, therefore movement of the story needs to move from the first frame. General rule a shot should not last longer than five seconds.
Narration for a book is structure in various compound and complex sentences for reading at a potentially uninterrupted rate. Narration for a film has to be written in phrases because it has to work with the sights and sounds of the film. When read for the ear, speaking pauses and pacing are key so that the words fit what is coming off the big screen.
Depending on the genre of a novel, and a comic book, realistic physics can be altered. Characters jumping, throwing punches and even surviving what would be normally fatal injuries can have liberties taken with them. Books can still live a very grounded reality, but it can be stretched. Watching something to that effect on a live action screen, suspension of disbelief can be harder to convey. There has to be a balance between fantasy and functionality.
A person’s preference for a movie to stick to the source material of a book is understandable, especially if there is a supreme fondness for the book. However, to always prefer a book over a film in every instance, is preference of medium as opposed to understanding the different storytelling functions.