[mythtv-users] OT: Why 3D TV won't work.

Simon Hobson linux at thehobsons.co.uk
Wed May 26 18:38:24 UTC 2010

Douglas Peale wrote:

>  > I don't think this is a fair comparison.  You are talking about
>>  perceiving 3D from a 2D image or seeing 3D in a real 3D environment.
>>  I would imagine the tricks to convince the eye and brain that
>>  something is in 3D for the former is much different than the natural
>>  way the brain has been trained through millions of years to perceive
>  > 3D in the world around us.

>How is it different? In real life, each eye gets a slightly offset 
>view of the real world. In 3D TV, each eye gets a slightly
>offset view of a scene. If what you suggest is true, we would get 
>headaches from watching 2D movies, because that is far more
>different from the way we see the real world than a 3D movie is.

It's far more complex than that. In the real 3D world, our brain 
decides where to look at at any point in time, and directs the eyes 
to adjust aim and focus to bring that point into both focus and 
register - every other point in our field of view is out of register 
and focus to some extent or other.

Take for example the simple act of holding up a finger in front of a 
distant scene. The brain can decide to look at the finger which then 
comes into focus while the distant scene becomes both unfocussed and 
out of register (the two eyes see the background in tow different 
places). Or the brain can decide to look at the distant scene when 
the finger goes out of focus and also appears in two places.

This all happens without us really thinking about it, and our brain 
takes care of moving the eyes and focusing them as required.

Now, lets turn to 3D TV or Cinema. We have a flat screen at a fixed 
distance - so one very important difference from real life. Second, 
only one point (or apparent distance) is in register at any point in 
time and that is set by the director when he directs the camera crew. 
If you don't happen to look at what the director thinks you should 
(perhaps you are curious about some detail elsewhere) then the images 
are "wrong" for where your brain thinks you are looking.
The focus is taken care of by having the screen so far away that in 
effect you only use distance vision. But you cannot escape the fact 
that if you look at anything other than the distance the director has 
set the 3D effect at, then the brain will move the eyes to coordinate 
at that distance, but the pictures won't be "right".

As already suggested, it may well work for fast action, since your 
attention will naturally be drawn to one thing - at least if the 
director got things right. But for anything where you might look 
around the rest of the scene then the images will just not work and 
the brain will get confused.

There's no way I'm going to say 3D will fail - I expect it will get a 
fair following. But I don't think it will be as compelling as other 
technologies which offer a clear benefit. Video cassette took off as 
it allowed home users to both record stuff, and to watch films when 
they wanted (without the hassle involved with the old film 
projectors). DVD took off as it offered the convenience of a small 
and relatively robust disk with random access as a bonus.

HD DVD (yes, I know it's now defunct) and Blueray haven't taken off 
**as much** as they offer very little to many people. Yes there's 
more detail, but many people either don't have the means to display 
it or can't even see the difference - there was a study recently over 
here in the UK where they found a significant number of people 
thought they were watching HD now they had their new LCD flat panel 
with the "digital tick" for Freeview and the "HD Ready" logos on it. 
Yes there are a good number of people prepared to pay the extra for 
the disks and equipment to play them, but disk sales are dwarfed by 
standard DVD sales.

I think 3D will go the same way. Some people will pay the extra, and 
they probably already have large screens, full HD, surround sound, 
etc, etc. The majority will simply decide it's not worth it, and 
they'll not bother unless the price comes down to "hardly any premium 
over 2D".

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

More information about the mythtv-users mailing list