Originally Posted by EatingPie
Okay, I haven't found the link, but I believe I know the issue with the negative parallax (Pop Out
) on the HMZ-T1.
In a cinema, you are far from the screen and your eyes are nearly parallel looking at almost anything. When things pop out at you, you start to cross your eyes to focus on it (think pulling your finger toward your nose and maintaining focus). But given distance to screen, you only need to cross your eyes a little bit when negative parallax (pop out) occurs. (I think the eye crossing is what causes fatigue.)
With the HMZ-T1, however, you are dealing with tiny distances, so you are forced to cross your eyes a lot more to maintain focus on a "pop out" object. You quickly reach a point of diminished returns, and the negative parallax breaks down because you lose focus... you can only cross your eyes so much!
As I said, I'm pretty sure this is from what I've read, but I could not find the link. So take it with a grain of salt.
I don't think that's it. Even though I don't have one of these yet, here's a (hopefully) easy to follow explanation of optical illusions.
Negative parallax, as with FOV, is about the angles. If you want to stare at your fingertip held 3" from your nose, your eyes are going to be crossed at pretty extreme angles, to the point where it is uncomfortable to maintain for any significant duration for most folks.
Achieving the 'effect' of something popping out of the screen and coming THAT close to you requires your eyes to cross at those angles, regardless of whether the image is displayed on 2 separate screens an inch from your eyeballs or on an 800" wide screen 60-70 feet away. This is also what the 'display size' settings in some players are there to compensate for. The manufacturers assume that most folks are going to be seated within a certain range from displays of certain sizes, for instance, they might assume a seating range of 7-12 feet away from a 55" TV, and a seating distance range of 10-15 feet away from a 130" FP setup.
Note that the FP setup is going to have a wider FOV than the TV setup because (with the exception of some crazy gamers), most folks don't really tend to sit within 4-5 feet from a 55" TV.
In order to achieve significant popout, the images on the 55" TV from 10 feet away would have to be further apart (as a ratio of screen width), and hence, closer to the edges of the display's screen than the same image on the 130" wide screen from 12 feet away (to achieve the same angle of negative parallax between your eyes).
The closest popout object I've ever seen in a mid-sized theater was the 3D demo in Universal Studios 15 years ago. Back then, they were using passive angular polarized glasses, so you got doubled images if you tilted your head from vertical, but if you held your head straight, there was this carton character that appeared to fly around the theater and then come to a stop directly in front of you, perceptually just out of arm's reach, then the character says, "Everyone thinks I'm talking to them, but I'm really talking to YOU" and when it says "You", it's nose elongates and appears to stick out to about 6" from your face.
The visual effect was SO good even back then, that it appeared to be an actual solid object floating in the air before you even though you knew it was a computer animated cartoon character. I found it particularly amusing that when it says "YOU", everyone, and I mean EVERYONE in the theater reached out in thin air and tried to grab/touch this cartoon character, even me LOL! I was so impressed by this short 3D experience that I went back to view it again, and in that scene, I closed one eye, then the other. The left eye image was quite close to the right edge of the screen and the right eye image was pretty close to the left edge of the screen. Your eyes need to cross that much to perceive an image/object as being that close.
To achieve that much of a popout effect required that the screen be quite wide (there has to be enough screen width to accommodate the crossed left and right eye images within its left and right borders).
The problem is that with no easy frame of reference (seats and people in a theater, objects in your HT/living room etc.) there is no frame of reference to popout. In my own room, when viewing 3D with popout, I'll usually sneak a quick glance at the room to see how far the image appears to be popping out of the screen. Is it popping out as far as my extended feet? Only as far as the center channel speaker? Somewhere in between etc?
With this display, there is no such frame of Reference, but if it's implemented well, as some folks have claimed, it should provide an incredible 3D experience that comes as close to simulating what you see in real life as can be duplicated with commercially available 3D displays these days. The image though, will have no frame of reference and the effect is going to be akin to what you see through a pair of ski goggles for instance. There is a real perception of 3D depth, you may not be seeing things that evidently pop OUT of the screen so to speak, although subjectively, they may appear to come very close to the viewer. How close though, is going to be entirely subjective.
The problem is that the perception is subjective, as someone else has illustrated from discussing how close the cod fish appears to come to each individual viewer under identical viewing conditions.
An odd test a few of us did out of sheer boredom in college was to see how good a person's depth perception was by having them sit in front of a bare white wall with flat lighting. We then had them close their eyes and we had an assortment of balls of different sizes that we mounted to poles using fishing line. The test subjects wore a simply made visor that prevented them from seeing the floor or ceiling as a frame of reference. A piece of cardboard served to block their vision completely, then we placed one of the balls in their field of view and gave them a quick look at the object (about 1 second) and then obscured their vision with the cardboard again and they had to decide if the ball was within arm's reach or not. It was amusing how many times people got it incorrect. All those UFO sightings where folks think they see a large object far away, moving erratically at super speed? Well, the experiment gave us an idea that they could have very well been smaller objects at much closer distances moving at earth attainable speeds.
That's also why estimates are all over the place as to whether it looks more like a 750" screen from the middle of a theater, or a 120" screen from 10 feet or a 2" screen from an inch away. People's opinions are subjective when they don't know how to obtain a frame of Reference, which is why I asked owner's to test the focal distance of the optics to compare how they focused on the image in comparison to focusing on something else in the room or outside a window.