The author creates the action and not its image. He cannot expect the whole crew to read every single detail of the author’s ideas about camera adjustments. It would be a hard task for everyone to leave out the parts that are not of interest for his competence in order to focus exclusively on the course of action.
Mostly, screenwriters are just not capable of giving good advices either. One of Syd Field’s bad examples for this case is novelist F. Scott Fitzgerald, who came to Hollywood to write screenplays. He studied all the camera related terminology like close-up, extreme close-up, and mid-shot and integrated it in his scripts, which, as a result, had to be rewritten.
Nevertheless, a few options to communicate your ideas of camera adjustments remain. The best of these is when the screenwriter is also the director or, at least, assists in the production of the film. This way, he can bring in his ideas in a discursive manner. Another is to write an additional camera script in collaboration with the camera team and the director.
But the most common way is to use phrases like ‘we see him from behind’, ‘the light is dimmed’, ‘her face appears between door and doorframe’, or ‘she just sees his shadow’. These are understandable to everyone, leave enough room for interpretation, and do not occupy too much space.
