How much should be used?

As a writer I've always wanted my work to be in its own featured film. However, in a recent discussion with a friend of mine about The Dark Knight Trilogy, it got me thinking. How much stuff should be used from the original source? This day and age almost everything comes from either a book, a comic or even a short story. I get that some things are important for the story and some things aren't. So how much do you think should be used in a movie?

I kind of mentioned in a previous post that as a fan I want as much of what I read to be in the film. However, is it really necessary? To a certain degree yes it is. I say that for this reason. In I am Number Four the movie, the last battle I thought was really sweet. Then I read the book and it was actually way more elaborate and action packed. At first I was like, why didn't they used that? I think it would have been fantastic to see that. It would've made the move that much better. To be honest, I think the movie conveyed it enough to show how power the Magadorians were and the story was made clear. I know there were some objections about some of the content. However, I think it was done well.

This is why I feel this way. There's a balancing act that needs to be done in a film. A director has to balance, story, character development and the action in a film to make it good. Now true certain films don't need a whole lot of story, mostly because they're meant to be a straight action film (Expendables). It has to be done in order for you the viewers to keep your attention and make it worth the $10 or more to see a film. I get that part, I still have my concerns.

I'm more worried when something is loosely based from the original source. Which implies they're going to take creative liberties with the characters, their origins and the overall story (Wolverine Origins). I understand that some things do not translate well on the big screen. Hence why X-Men uniforms were black and leather and not the normal blue and yellow spandex. I did like the improvement on it in First Class, but it wasn't necessarily spandex.....let me move on. My concern is when the foundation of the character and their drive is changed for some odd artistic liberty humans want to take. I don't get it sometimes.

Now I know we can't get everything in a film. That's why I hate when people want at least several years of story to be put into a 2 hour film. It's completely unrealistic and unreasonable. At the same time, it shouldn't be so bare bones that we lose the reason why we love these books or characters. It's not an easy act to balance that out, however, it has been proven that it can be done. Just think about it Fox when doing this next Wolverine movie. You almost had it with The Wolverine......almost.