"clipka" <nomail@nomail> wrote:

>
> There appear to be different technologies out there, but state of the art
> actually is not horizontal and vertical polarization, but left-handed and
> right-handed circular polarization -- the advantage being that you don't need to
> keep your head exactly level.
>

I was in Las Vegas USA many years ago, and watched a 'special venue' 3D movie
there on a large domed screen. (Some form of IMAX, probably.) I *think* the 3D
glasses I wore were shutter glasses of some sort (but I could be wrong; I don't
remember exactly.) The 3D effect was flawless-- and I was amazed that I could
turn at any angle to look at the imagery, even directly overhead. I assume the
3D glasses were circularly-polarized-- my first experience with that technology.

But when I went to see AVATAR in 3D-Imax at my local big cinema, I remember
tilting my head to see what would happen-- and instead saw two overlapped images
in each eye, with no 3D :-(  The glasses they gave out (on loan!) were simple
polarizers, nothing active. So no circular polarization there, AKAIK.

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On 1/8/2016 3:32 PM, Kenneth wrote:
> "clipka" <nomail@nomail> wrote:
>
>>
>> There appear to be different technologies out there, but state of the art
>> actually is not horizontal and vertical polarization, but left-handed and
>> right-handed circular polarization -- the advantage being that you don't need to
>> keep your head exactly level.
>>
>
> I was in Las Vegas USA many years ago, and watched a 'special venue' 3D movie
> there on a large domed screen. (Some form of IMAX, probably.) I *think* the 3D
> glasses I wore were shutter glasses of some sort (but I could be wrong; I don't
> remember exactly.) The 3D effect was flawless-- and I was amazed that I could
> turn at any angle to look at the imagery, even directly overhead. I assume the
> 3D glasses were circularly-polarized-- my first experience with that technology.
>
> But when I went to see AVATAR in 3D-Imax at my local big cinema, I remember
> tilting my head to see what would happen-- and instead saw two overlapped images
> in each eye, with no 3D :-(  The glasses they gave out (on loan!) were simple
> polarizers, nothing active. So no circular polarization there, AKAIK.
>
>
>

I got a headache watching Avatar, but the new Star Wars was okay. Maybe 
they used different technologies?


Mike

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Am 08.01.2016 um 21:51 schrieb Mike Horvath:

>> But when I went to see AVATAR in 3D-Imax at my local big cinema, I
>> remember
>> tilting my head to see what would happen-- and instead saw two
>> overlapped images
>> in each eye, with no 3D :-(  The glasses they gave out (on loan!) were
>> simple
>> polarizers, nothing active. So no circular polarization there, AKAIK.

Circular polarization isn't necessarily active either. Not sure if it's
even suited to make shutter glasses out of it. It's just another
polarization mode of light.


> I got a headache watching Avatar, but the new Star Wars was okay. Maybe
> they used different technologies?

It simply depends on the theater; both movies can be shown with either
technology.

When I watched Avatar, they already had the very same circular
polarization glasses with slight green/cyan tint.

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Am 08.01.2016 um 22:21 schrieb clipka:

> When I watched Avatar, they already had the very same circular
> polarization glasses with slight green/cyan tint.

Just did a bit of browsing on the 'net, to find out that I'm entirely
mistaken; so here's the deal about professional theater 3D technology:


IMAX 3D:
--------
Steer clear of these theaters. They use linear polarization, i.e. the
thing that makes you not want to tilt your head.

Needs a special silver screen.
The glasses may be compatible with some passive (i.e. non-shutter) 3D TVs


Cinema 3D:
----------
Never seen or heard of these brands before myself, but should be ok.
They use circular polarization.

Needs a special silver screen.
The glasses may be compatible with some passive (i.e. non-shutter) 3D TVs.


Real-D:
-------
Never seen or heard of these brands before myself, and not sure what to
make of these theaters. They also use circular polarization, but employ
a shutter-like apparatus in front of the single projector, which I
suspect might be more prone to giving you a headache due to flickering.

Needs a special silver screen.
The glasses may be compatible with some passive (i.e. non-shutter) 3D TVs.


XpanD 3D:
---------
Never seen or heard of this brand before myself, and not sure what to
make of these theaters. They use shutter glasses, which I suspect might
be more prone to giving you a headache due to flickering.

Does not need a special silver screen.
Does need expensive glasses, which /are/ probably compatible with active
(i.e. shutter) 3D TVs.


Dolby 3D:
---------
This is what I was referring to, and they're a perfectly good choice,
but they do /not/ use circular polarization. Instead, amazingly it /is/
a variation on the old red/cyan theme. BUT: Rather than two broad colour
channels, one for each image channel, they use /six/ narrow colour
channels, assigned to the image channels in an alternating fashion; this
significantly reduces the apparent colour shift, as each eye gets its
own R, G and B channel, albeit with slightly different primary hues. The
residual shift is noticeable as a slight red/cyan tint of the glasses,
but is completely eliminated in the projection by digital colour correction.

Doesn't need a special silver screen.
Does need expensive glasses -- which are /not/ compatible with /any/
contemporary 3D TVs.

(Not to be confused with the display technology of same name that is
currently being developed for home use, and allegedly will not need any
glasses whatsoever.)


Given this broad range of 3D theater technology in current use, I'm not
/that/ surprised anymore to hear entirely different opinions about the
3D movie experience.

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Am 08.01.2016 um 23:44 schrieb clipka:

> Cinema 3D:

Forget about this brand name; apparently it's not a 3D theater
technology, but a 3D TV/monitor technology.

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On 01/07/2016 06:51 PM, Alain wrote:
> Le 16-01-07 19:01, Mike Horvath a écrit :
>> I just got done watching the new Star Wars movie in 3D. I kept the
>> glasses. How do I make images like that in POV-Ray?
>>
>>
>> Mike
>
> The 3D glasses used for colour movies normaly use polarised glasses, vertical
polarisation on
> one side, horizontal for the other.

A point of trivia...  I know for a fact that the original 3D movies did not use 
horizontal/vertical polarization -- they were both at 45°, one was / and the other
was \.  I 
*assume* this is still the case but don't know.

Aside:  My father used to be a projectionist, and over the years worked at several
different 
theaters.  So when I was young (a llooong time ago) I got to see movies for free
anyplace he 
worked.  He retired, then later passed away quite some time ago, so these days I have
to pay. 
:-(   So I rarely go to movies anymore (I'm cheap!)  ;-)

      -=- Larry -=-

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On 1/7/2016 7:01 PM, Mike Horvath wrote:
> I just got done watching the new Star Wars movie in 3D. I kept the
> glasses. How do I make images like that in POV-Ray?
>
>
> Mike

I did a bit of browsing of Amazon looking for a nice stereoscope. 
However, they run between $40 - $100 which is too much.


Mike

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Am 10.01.2016 um 01:53 schrieb Mike Horvath:
> On 1/7/2016 7:01 PM, Mike Horvath wrote:
>> I just got done watching the new Star Wars movie in 3D. I kept the
>> glasses. How do I make images like that in POV-Ray?
>>
>>
>> Mike
> 
> I did a bit of browsing of Amazon looking for a nice stereoscope.
> However, they run between $40 - $100 which is too much.

Indeed, given that Google Cardboard and variations on the theme are
around $30 bucks. If 3D image viewing is all you want, and you happen to
own a smartphone, that might be an alternative to examine. (And if you
happen to not own a smartphone, it might be worth investigating whether
you can convert one of those into a classic stereoscope ;)

Also, if you even happen own a Samsung Galaxy Note 4 or 6, Samsung's
Gear VR might definitely be worth a look.


And of course Oculus are now accepting pre-orders, but their price is in
an entirely different ballpark B-) (unless you compare it to Samsung's
Gear VR /plus/ a brand-new Samsung Galaxy).

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On 1/9/2016 9:04 PM, clipka wrote:
> Am 10.01.2016 um 01:53 schrieb Mike Horvath:
>> On 1/7/2016 7:01 PM, Mike Horvath wrote:
>>> I just got done watching the new Star Wars movie in 3D. I kept the
>>> glasses. How do I make images like that in POV-Ray?
>>>
>>>
>>> Mike
>>
>> I did a bit of browsing of Amazon looking for a nice stereoscope.
>> However, they run between $40 - $100 which is too much.
>
> Indeed, given that Google Cardboard and variations on the theme are
> around $30 bucks. If 3D image viewing is all you want, and you happen to
> own a smartphone, that might be an alternative to examine. (And if you
> happen to not own a smartphone, it might be worth investigating whether
> you can convert one of those into a classic stereoscope ;)
>
> Also, if you even happen own a Samsung Galaxy Note 4 or 6, Samsung's
> Gear VR might definitely be worth a look.
>
>
> And of course Oculus are now accepting pre-orders, but their price is in
> an entirely different ballpark B-) (unless you compare it to Samsung's
> Gear VR /plus/ a brand-new Samsung Galaxy).
>

My smartphone has a low resolution 480 x 854 pixels (~221 ppi pixel 
density), and it's a Windows Phone, so there are few apps for it.

http://www.gsmarena.com/nokia_lumia_635-6254.php

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Le 16-01-09 19:53, Mike Horvath a écrit :
> On 1/7/2016 7:01 PM, Mike Horvath wrote:
>> I just got done watching the new Star Wars movie in 3D. I kept the
>> glasses. How do I make images like that in POV-Ray?
>>
>>
>> Mike
>
> I did a bit of browsing of Amazon looking for a nice stereoscope.
> However, they run between $40 - $100 which is too much.
>
>
> Mike

In several cases, you don't realy need a stereoscope.
If the images are side by side, and suficiently small, then parallel 
viewing can work nicely. You look at the images as if they where farther 
away than they are.
Often, when the side by side images are larger, you need to use the 
crosswed eyes viewing method where you cross your eyes as if the images 
where much closer than they actualy are.
Cost: Free.
With some practice, it won't cause eye fatigue. I can use bot parallel 
and crossed view for hours.

If the images are supposed to be viewed with polaroid filters, you can 
repurpose old polaroid sun glasses by removing the glasses and mounting 
them in a cardboard frame at the correct angles.

Obviously, if you need shutter glasses, then, you just can't make a home 
made version and need to buy some that are compatible with your equipment.

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