Something I found in the comments:
Regarding Kubrick’s thoughts about actors: OK, much to my surprise, I’ve never heard anyone talk about this before, and, assuming I may be right, and other’s pick up the idea, I’ll lose credit for pointing this out, but … consider Kubrick’s use of books in his movies. As meticulous as he is, one might suspect that he picks the prop book for very specific reasons, up to and including which page is shown on screen. Now, consider a scene, early in The Shining, where Wendy is talking to Danny at the table while reading a book. (YouTube: “The Shining Scene: Wendy talks to her Son, Danny”). The book she is “reading” is The Catcher in the Rye. During her conversation with Danny, Duvall seems to intentionally let the page she is reading be seen by the camera, even holds the book open rather than closing it, as if it were directed. If nothing else, Kubrick certainly frames it in the shot, both the cover and the page. Interestingly, the corner of the opposite page she is reading is turned down, and it is the ONLY page marked like that, suggesting the possibility that Kubrick wanted Duvall to have the book open to that specific page. So I pulled out my copy of Catcher, and, based roughly on where the book was opened, and the arrangement of the paragraphs, I looked for the page to see what might be on it that could be relevant to the story or to Kubrick. Here is the passage I found: “I hate actors. They never act like people. They just think they do. Some of the good ones do, in a very slight way, but not in a way that’s fun to watch. And if any actor’s really good, you can always tell he knows he’s good, and that spoils it.” One caveat to this proposed possibility is that my copy of Catcher is the 19th Bantam printing, printed somewhere during or shortly after 1967, and the copy Duvall is holding appears to be slightly larger than my copy, suggesting that it is one of the other 52 printings made during or prior to 1967, or perhaps a printing post 1967. As such, the size and location of the paragraphs on the page may differ between the two copies, which opens up the possibility that the passage I found is just a coincidence.
I knew a couple of technicians who worked on FMJ. The news cameraman who appears in the film is John Ward who was the Steadicam operator on the movie. I assisted him on quite a few film jobs back in the day. He told me that towards the end of one day, light-wise, there was a protracted disagreement between Kubrick and Milsome the D0P, about how taking the #85 filter off, to gain an extra 2/3 of a stop, and consequently more time for shooting, would effect the ASA rating of the tungsten film stock they were shooting with. Someone else told me that the film got through quite a few focus-pullers, one of whom, having taken in Kubrick’s view, an inordinate time to get the many focus points needed for a long lens shot, was fired after 5 takes.