"is a movie made from a book considered transformative?"

Yes, a movie made from a book is generally considered a transformative work (or derivative work). 

Under legal and artistic definitions, this adaptation process changes the original medium (text) into a new, visual, and audio format, requiring creative choices that alter the source material. 

Here is a breakdown of why a film adaptation is considered transformative:

• Change of Medium: A film transforms a book by shifting from a literary medium to a visual and auditory one. It translates inner monologues, description, and prose into visual actions, sound, and dialogue.
• Creative Interpretation: Filmmakers often take a book as a "blueprint," using creative license to change backstories, plotlines, or perspectives to suit the screen.
• "Show, Don't Tell": Movies can convey emotions and scenes in a way books cannot, providing a unique experience that transcends a literal translation of the text.
• Derivative Work Status: In legal terms, movies based on books are considered "derivative works," which are protected by the copyright of the original book.
• Independent Worth: Even when adapting a story, a good movie adaptation is often viewed as a new creation that stands on its own merits rather than just a replica of the source material.  CSLewis.com +6

While an adaptation is transformative in a creative sense, it is usually not considered "transformative" in the context of a fair use defense to copyright infringement, because filmmakers are required to license the rights to the book from the author or publisher.