The Ultimate 3D projection system: A Practical Discussion Thread - Page 2

I'm guessing the glasses could be simpler than the projector filters. The glasses only need to block the three wavelengths from the wrong eye perspective. The projector filters need to block all wavelengths except the three for the correct eye. Using the narrow bandwidth projector filter for both the projector and glasses would of course also work. Don't know if that's how it's implemented though.

Using lasers or narrow band width LEDs with the right wavelengths as light source you wouldn't need any projector filters, as you say, and the total light efficiency should be really high.

Many reasons to move away from bulb based light sources.

Very good point, that would explain why the attempts to use the glasses on the projector caused a lot of ghosting, it's not blocking everything it should from the lamp. As you say, the glasses could be "bandcut" while the projector filter could be "bandpass". It's also possible that the "bandcut" glasses are either more efficient or much less expensive to produce.

The only way to know would be to measure the glasses... not sure what equipment to use though...

Darin. I don`t remember where I read it, perhaps in a mag article or a white paper comparing the various efficiences of linear polarizer systems, circular polarizer systems, shutter glass systems, and the Infitec or dolby system. obviously there are variables such as for polarized two projectors, two filters, or oe projector and a single panel polarizers that switches polarity through electronics or whatever. Or various light spectrums or improving filter glass technology or shutter glass technology (more transmissive when not blocking) etc. The fiqure usually qoated for shutter glass systems operating at 144 are 83% and for dolby or Infitec (same thing) 94%.

And the real interesting figure is how much light they let through. In this case 17% and 6%, respectively. That means that the shutter glass approach is almost 3X more efficient. Makes you wonder how the manage to do it at all at commercial cinemas with Dolby 3D, and now we're talking huge screens...

I'd be curious to check those 6 wavelengths against a xenon bulb versus a UHP bulb. I assume those theaters using dolby are most probably using xenon lamps ?
Since the whole dolby system is limited to the lowest emission of any of those 6 colors, and a UHP bulb has a very ugly emission graph, it could very well be much better with a xenon, as it's not that bad across most of the visible light.
But I haven't found what the wavelength are, nor the width of each color

Or maybe those cinemas calculated that the cost of a more powerful projector was less than the installation cost of a silver screen. They had to change the projector anyway for 3D. I look at the 3000$ for a small home theater Stewart, and I imagine a cinema screen must be very very expensive

Actually, I have seen RealD 3D three times and Dolby 3D one time, all on big screens. I actully think the Dolby was the biggest one. And I can say for certain that the Dolby 3D was the brightest! By far! The RealD systems made you long for more light, but the Dolby not so. Makes you wonder what kind of projector, and bulb, they used.

Mark, I just read my post again and realized that, in an attempt to be accurate, I actually came across as a bit of a dick. (insert your smart assed reply here)

Please accept my apology.

The filters on the machines block the same frequencies that the filters on the glasses block as I understand it. Ideally what I filter on the machine passes for one eye one would want the glasses filter for that eye to pass. I am wrong?

What happens when you put the left lens over the right lens ? is it black ?

I don`t know what happens in theInfitec system. With polarizers, if the polarizers are perfect, a 90 degree rotation between two of the same should block all the light. Since nothing is perfect, probably some light would pass through. Darin has the Infitec lenses out of the glasses. What happens Darin?

CM. No need to apologize. Really, I have the utmost respect of you despite an occasional idiosyncrasy.

Now on occasion but not a large percentage of the time you are a bit of a Dick. This might be due to you having a small one or something else. Frankly, I don`t want to know.

But occasionally we all get checked into the boards. Usually all I heard on such an occasion was a Canadian accent Bahuuuuuuuteeeee.

As a famous dead US President once said, Walk softly but carry a big stick. I do. Very big. Bahuuuuuteeee.

Now kids lets play nice

group hug !

You guys ever see him? You can hug him, not me. And we are not fighting. We respect and like each other. Its just that he is shy in real not internet life. you can hug me if you are an extremely good looking lady and promise not to file charges if I group you during the hug. I am cute and loveable even if properly classifiable as an old geezer. CM is an young geezer. Over the hill but not so far down the other side of the mountain that he can`t still see the top even though he can`t reach it anymore.

Very interesting thread. I think I'm going to go the cheap route for 3D while you guys sort all this stuff out for me!

Another advantage of Infitec versus other technologies that might not be discussed here, is the fact that the "real world" looks very bright compared to shutter glasses, that basically dims your surroundings a whole lot.

With Shutter glasses you can barely see anything at all other than the screen (this isn't that big of a deal on pitch black theaters to begin with i guess.)

With Infitec glasses however, you can look around with out any real light loss if your 3d rig has some ambient light on purpose for the sake of being able to see around you.

I'm really starting to consider buying a cheap (and i mean cheap if anyone wants to sell ) extra RS1x so i can just run an infitec setup again, if i could find a way to color correct infitec on my HTPC, it'be a no brainer for me, it's the one thing holding me back for searching for a second projector instead of buying a brand new RS40.

You can buy, if you play it right, an Infitec color correction box for about $6K from the US Infitec Importer.

That's actually a disadvantage. The shutter glasses are increasing contrast compared to the Infitec by dimminishing the ambient light.

Well, lets just call it a double edge sword.
Because that's actually a really good point.

I asked you for a source and instead you just say that is how it works. Honestly, I get the feeling that you don't really know, are making an assumption, and passing it off as fact here. Maybe you actually do have some information to back this up, so please provide it if you have it. I'm not trying to get personal, but I know your history enough that I'm not going to be naive and just trust what you say without something to back it up. Especially when my initial measurements don't seem to support what you claimed (although it can get complicated and I wasn't mapping wavelengths, just total measured light).

Good question. It is pretty dark, but not black to my eyes. But our eyes can adjust a lot. At one point I calculated that this blocked about 299/300th of the light (letting about .3% of the measured light through), but that could have been off depending on changing room conditions, which could have put it closer to 1% of the light that a high end meter measures making it through both lenses.

I also found that the angle of the lenses was very important. A little tilt could change the measured light significantly. I'm just going to give my final figures after realizing it was important to make sure the lenses were very perpendicular to the projector lens and meter lens.

I used a Minolta LS-110 that measures light off the screen and all measurements are in cd/m2. One of the lenses lets light through that looks very green and one very red, so I'll call them by those colors (and refer to them as filters). My room was getting a little bit of light into it and with the projector blocked and no Dolby lens on the meter I was getting about .01 cd/m2 near the end.

Here is what I got for measurements with a 100 IRE full screen image with an Epson 9500UB:

No filters: 51.8
Green filter on projector: 33.9
Green filter on projector and green filter on meter: 26.9
Green filter on projector and red filter on meter: .23

Red filter on projector: 8.8
Red filter on projector and red filter on meter: 7.4
Red filter on projector and green filter on meter: .16

I should probably mention that when I first started doing the measurements my room was getting enough light in that I measured .11 with the projector blocked and it wasn't too long after that when I tried putting both filters over the projector and measured .23 off the screen with no filter on the meter. But I don't know if the room light had changed by then.

As far as total light loss with this projector with a UHP lamp it looks like it goes from 51.8 to 34.3 if both eyes are added, or 17.2 if both eyes are averaged. Or a 67% loss if using the average of both eyes. I suspect that the 94% loss claim was not with a UHP lamp like this projector uses. Of course my figure doesn't take into account any color balancing.

--Darin

And he does all this despite not having a 3D source. You are a mountain. Sir Edmond. Me? I just spend my time watching sports on my 2D projector.

If the two SIM2 projectors start out at about 3000ANSI each or 6000 for the pair and you take away 94%, does that mean we were watching 360ANSI? It seemed much brighter than that.

Also, with the Infitec system, aren't the two projectors in essence displaying slightly different coordinates on the SMPTE chromaticity chart?

Who is the US Infitec importer?

As you are referring to ANSI lumens, the system brightness is actually 9000 or 4500 each.

Did you think I was not going to find this subversive comment buried in this forum Mistress Fellateeoh?

She is lying again..... FIND OUT THE TRUTH.

Peter, read my post again FFS, there is nothing you need be concerned about, or that refers to you in any way. Certainly nothing that warrants you interrupting your salad tossing activities.

I simply point out that the range of 3D is from excellent to crap, and that I did not need to attend CEDIA to be aware of that.

Kudos on taking the most tenuous of links and converting that into a blatantly opportunistic bout of self aggrandizement.

I shall redress this minor ad hominem elsewhere.