I've noticed that over the last few years movies, videos and TV are cropping people through the forehead, It came to mind while watching the latest LL video journal. Is this a modern technique/style? It seems to be more prevalent now with wider aspect ratios. It doesn't really bother me just different
There is really no hard and fast "rule" about headroom except that there's always someone who will say it's wrong:) In my camera operating career I've heard many comments like "never cut off the hair!" Or "Never cut off the chin" or, just the opposite. You have to use your own artistic judgment keeping in mind the purpose of the shot in your story, and sometimes, what shots will intercut with it, and how they were shot.
My favorite story is from years ago when I was operating on a major network cop show and we had a scene of hundreds of singing "homeless" people. I moved in for a close-up at the climatic moment on one of the "homeless" and ... cut off not only the hair, but the eyes, focusing on his open mouth. Boy did I get yelled at! Horrible things about how stupid I was, that it was AGAINST THE RULES OF COMPOSITION! I went to the studio to see the "dailies" the next day (back when even tv was projected on film in a theater). When my shot came up, the producer jumped up and exclaimed "That's the shot!"
The series was cancelled after just 6 episodes were aired:)
One thing to consider though, is the size of the screen. An image shown in IMAX or a large movie theater usually needs a little more headroom than a frame meant for the small screen or the web.