Here’s a secret:
Sometimes I watch the movie before I read the book.
This is a point of contention with some readers; mainly they feel that the original text is sacred and you should read the book first. No matter how good the movie is, no matter how closely they follow the book, the visual piece can never be the same as the book. And I tend to agree with them.
But here’s the thing.
I’m one of those people who can’t visualize characters and places very well, so watching the film adaptation is actually really great for me. If I read the book first and then see the movie I can say “Okay, this is sort of how I pictured it,” or “this character was hard to picture, okay, that’s what they look like.” Or if I watch the movie first I can visual the characters better first.