Warren Manser started out working for Sam Raimi on Army of Darkness,
Here's what he told io9 about the difference between being a comic book versus a concept artist.
"Concept art differs from comic art and book illustration in many ways. It is extremely rare that a concept art piece is actually seen by the audience, whereas other forms of illustration display a faithful reproduction of the art piece itself.
Concept art depicts a set, scene, or object that will be built by carpenters, model makers, or digital artists, so the concept artist has to have some idea of the reality of the final product.
And, the concept art piece can be created to depict its subject in a cinematic manner. That is, in some instances a 2D piece that is illustrated, however beautifully, potentially depicts a scene that can not be shot with a camera."
This a profound statement. A concept artists job is to take a two-dimensional image and portray it in a way that allows those working on the film to see it in three-dimensions. That takes a lot of skill.
If you'd like to read more about him check out "The Art of the Matrix
I was hoping to get permission to feature some of his work on this blog, but, for now, just head over to the gallery on his website for more.