3D with home TV: why need new monitor?

[Peroxyde]

Hi,


I apologize in advance for a lot of silly questions. Samsung and Panasonic had released some 3D TVs last week. They need a pair of shutter glasses to see 3D. The TV and the glasses are very expensive.

I watched Avatar in 3D in a movie theater and wearing a pair of glasses that seems not very expensive. And the 3D effects were really amazing.

I wish it was possible to use the same cheap pair of glasses and using the TV at home to watch 3D. But I guess it is technically impossible. What is the reason?

Here is another dumb question. A 2D movie looks pretty good on current TVs or computer monitors compared to a 2D at the theater. Why is it different with 3D? What are the quality or properties a home equipment should have in order to have nearly the same 3D effects than Avartar at the theater?

Thanks in advance foir any enlightenment.

 

[Koing]

2D looks bad in the cinema? The cinema your going is not setup correctly. It should look great in the cinema if you go to a decent one with a decent setup. OR the 3D stuff is just newer and better calibrateda nd the 2d stuff they have is old? Thats very possible.

Koing

 

[tuskers]

Two things: If you go to most "average" theaters, the contrast ratios on the projectors are pretty terrible. Blacks aren't close to black, they're barely dark gray in some theaters. Plasmas and LED-backlit LCD TVs reproduce very accurate blacks-- if a light is on in the room and the TV signal is all-black, then you may not even be able to tell the TV is on.

 

[Fallen Kell]

3D in cinema is many times performed with 2 projectors, each with a different polarized lens (the two are polarized 90 degrees out of phase from each other, and such that image for the "left" eye is polarized in the same orientation as the "left" lens of the glasses, and vice versa. Because if you polarize the light and then use a polarized film that is 90 degrees out of phase from the light, no light will pass through, thus the left eye only sees the light from the lens showing the left picture, and vice versa, the other is blocked).

The TV on the other hand, does not have two separate polarized lenses to send different polarized light output. So, it do it by showing alternate frames, left eye frame, and then right eye frame, and relies on shutter glasses to sync to the TV stream. The TV also has to be able to refresh the image fast enough so it can handle the effective doubling requirement of the number of frames it shows for a single second of images.

 

[Murloc]

refresh rate.

In the theather they use xpand glasses which are shutter glasses as well, they cost around 100 CHF and aren't cheap.

 

[Fallen Kell]

Murloc, not all use xpand glasses, for the very reason you listed, they are expensive and they require power source to work.

Many theaters won't use them because usually 5-10% will walk out the door with the customers. Even at $50, that is around $500-$1000 lost per showing in a 200-250 seat theater that is full. They only made $2000-2500 in ticket price for those seats... doesn't take long to realize that operation is not sustainable (especially since they still have to pay their portion of sales back to the movie studio/distributer, taxes, employees, and facility with the $2000-2500 as well).

Which is why it is much cheaper to purchase another $25-30k projector.

 

[EightySix Four]

3D in cinema is many times performed with 2 projectors, each with a different polarized lens (the two are polarized 90 degrees out of phase from each other, and such that image for the "left" eye is polarized in the same orientation as the "left" lens of the glasses, and vice versa. Because if you polarize the light and then use a polarized film that is 90 degrees out of phase from the light, no light will pass through, thus the left eye only sees the light from the lens showing the left picture, and vice versa, the other is blocked).

The TV on the other hand, does not have two separate polarized lenses to send different polarized light output. So, it do it by showing alternate frames, left eye frame, and then right eye frame, and relies on shutter glasses to sync to the TV stream. The TV also has to be able to refresh the image fast enough so it can handle the effective doubling requirement of the number of frames it shows for a single second of images.

Why can't the glasses sync with the blu-ray player instead of the TV. For example, a plasma can do 600hz or so, which is more than enough. Obviously there is a problem with TVs taking time to do post processing, but it should be easy enough to adjust the delay with an on screen setup.

 

[Cybordolphin]

I have a question.... what does TMT3 mean when they tout that the software makes 2d DVD's play in 3D???

 

[JackBurton]

Why can't the glasses sync with the blu-ray player instead of the TV. For example, a plasma can do 600hz or so, which is more than enough. Obviously there is a problem with TVs taking time to do post processing, but it should be easy enough to adjust the delay with an on screen setup.

Plasmas refresh at 48, 60, 72 or 96Hz not 600Hz. That is the subfield drive (600Hz) which has nothing to do with the actually displays refresh rate.

 

[Muadib]

Plasmas refresh at 48, 60, 72 or 96Hz not 600Hz. That is the subfield drive (600Hz) which has nothing to do with the actually displays refresh rate.

Taken from a Panasonic site:

What is 480 Hz sub-field drive?
A standard video signal is actually a series of still images, flashed on screen so quickly that we believe we are watching a moving image. The typical frame rate used in North America is 60 frames per second (60Hz) meaning that a TV would display 60 individual still images every second. Sub-field drive is the method used to flash the individual image elements (dots) on a plasma panel. For each frame displayed on the TV the Sub-field drive flashes the dots 8 times or more, meaning that the dots are flashing 480 times per second (480Hz) or more. (Example: 60 frames per second x 8 sub-fields = 480 flashes per second)

So 600 Hz would be 10 sub-fields x 60 frames per second.

 

[0roo0roo]

theres no easy way to polarize alternating frames on flat panels.
dlps you might be able to.
no one buys those.
with flat panel to separate frames you need shutter glasses.
but then you cut light because lcd shutter is polarized, and 50% of the time each eye is blacked out meaning 50% loss of light++
3d doesn't scale down without adjustment apparently either.
for games it might be ok. value is questionable on most non huge sets.

 

[Peroxyde]

Hi,

Thanks to "Fallen Kell" and "0roo0roo", I now understand the hardware limitation of current TV / Monitors.

Let's assume I have a modern 3D TV. But I don't have enough shutter glasses for everybody. What do the people without shutter glasses see on the screen?

Is it a normal 2D image that we can watch for any length of time. Or is it something blurry that will incur headache in a few minutes?

 

[citan x]

So if I already have one home theater projector, could I just add a second and have 3D as well? and use the cheap glasses?

 

[Muadib]

Hi,

Thanks to "Fallen Kell" and "0roo0roo", I now understand the hardware limitation of current TV / Monitors.

Let's assume I have a modern 3D TV. But I don't have enough shutter glasses for everybody. What do the people without shutter glasses see on the screen?

Is it a normal 2D image that we can watch for any length of time. Or is it something blurry that will incur headache in a few minutes?

The image for those without glasses will be blurry, forcing you to turn off the 3D until you go buy more 3D glasses, which currently cost $150 a pair.

 

[Craig234]

I saw a good article on why 120Hz is needed for tv 3d.

My question is, is there a fix for the way it makes the image 50% darker?

I tried out the nvidia 3f glasses for gaming, and it was a combination of 'nice 3d' and 'this is much too dark'.

 

[0roo0roo]

Hi,

Thanks to "Fallen Kell" and "0roo0roo", I now understand the hardware limitation of current TV / Monitors.

Let's assume I have a modern 3D TV. But I don't have enough shutter glasses for everybody. What do the people without shutter glasses see on the screen?

Is it a normal 2D image that we can watch for any length of time. Or is it something blurry that will incur headache in a few minutes?

they see whatyou'd see at the theater without the glasses on, a double image.

newer 3d tvs will also need to be faster pixel wise, and there will be no fudge factor in the pixel response measurement because the short period of time that shutter is open for each eye means that pixel must be the right color, not on its way to it when the shutter opens.

and 2d...it should look better in any decent theater, film far exceeds hdtv resolution. shifty theater or cr@p projectionist can mess up focus or dim the projection bulb for saving cash sometimes, but i haven't seen that in big chains.

 

[0roo0roo]

I saw a good article on why 120Hz is needed for tv 3d.

My question is, is there a fix for the way it makes the image 50% darker?

I tried out the nvidia 3f glasses for gaming, and it was a combination of 'nice 3d' and 'this is much too dark'.

nope, thats inherent to the tech, if each eye is turned off for 50% of the time,+ polarized filter in each lcd by default..much light is gone. so any decent 3d monitor should be able to go into over bright mode as well to compensate.