Originally Posted by Jedi2016
Some TVs (the TV, not the player), have a "3D depth" setting, or something named similarly, that will forcibly adjust the distance between the left and right eyes.
"3D Viewpoint" on LG TV's is a convergence setting only. It just pans the left and right eye images horizontally. I wouldn't call it "distance between the left and right eyes," because that's interaxial (lateral positional movement only possible in games that are rendered in realtime). Interaxial is hard-coded at the time the movie is recorded. I say this not for your sake, as I'm sure you know this already, but for the sake of the people you're trying to educate, because they might confuse the two if they hear a trigger word like "distance."
Adjusting the separation manually moves the convergence forward or backward, so that the 3D "focus" of the shot is now on some random object in the scene rather than the central focus as determined by the director, cinematographer, and stereographer.
Again, not to slap you on the back of the hand twice in one post, but for the sake of others who might potentially be confused, I want to discourage you from saying "separation" when describing convergence. It's just hard for people who don't know the difference between convergence and interaxial spacing.
That's why I have an issue with changing it, you're altering the focal point of the shot.[
I'm out of this mentality that the screen plane matters. There is no TV, there are only four walls cutting off the image. Setting the viewpoint at a positive value pushes the scene further away while increasing the sense of scale to that of a theater. Shift it to a negative value and everything begins to float closer to you, which can feel dreamy. The only objective downsides to adjust convergence away from default are potential eye strain and crosstalk, which will vary from person to person and TV to TV respectively.
I've never even bothered to learn where that setting is on my TV. The only button I bother with is "3D on/off".
As I said, it has its benefits. I usually shift things positive for a slightly larger sense of scale. But I've been wanting to re-watch Life of Pi with it set to negative, not because I'm a sucker for popout gimmickry, but simply because negative parallax can be mesmerizing emotionally, like the popout faces in a few instances in Hugo to make the audience feel more connected to that character.
Shot depth and convergence is based on more than just pushing things forward or backward. The convergence is set very carefully, shot by shot, by the people with decades of filmmaking experience, and it seems pretty arrogant to just throw all that away in favor of a gimmick, without even considering things like edge-breaking. How many of you who push your settings for more pop-out even know what it means to break the edge, or why it's a bad thing?
I wouldn't consider negative parallax to be a gimmick-- what's a gimmick is when there's a sword or spear coming out of the screen pointing at my nose for no story-driven reason at all.
I know the importance of convergence; I abided by the rules in all my stereo content: http://www.youtube.com/user/MuchRockness/search?query=yt3d
I was very consistent from shot to shot, making sure you could relax your eyes and have each shot be in focus with minimal eye adjustments. But when you change the viewpoint on the TV, you just readjust your eyes once and then your eyes are set for the entire movie. Sure, movies are designed so that your eyes focus on the same point they converge on for the majority of the 2 hours, but as you get more used to viewing 3D the negative side effects associated with that disconnect diminish.
Again, I disagree with the theory that we must be conscious of where the plane of the screen is as if its position relative to the content in the movie matters. What matters is the relative position of something at infinity vs something that's meant to be in the extreme negative parallax. The stereo windows are a distraction I'm trying to avoid focusing on, because they're really irrelevant to the story. The only exception I can think of where the window is important is when Raimi conjures flames and a tophat to fly out of the 4:3 frame in the movie Oz: The Great and the Powerful. When I saw that I thought it was a pretty clever homage to old 4:3 films.Edited by cakefoo - 4/29/13 at 11:58pm