The Ultimate 3D projection system: A Practical Discussion Thread - Page 78 - AVS | Home Theater Discussions And Reviews
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post #2311 of 2321 Old 02-14-2015, 12:20 AM
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Quote:
Originally Posted by wanderer View Post
I'm going to post some information in the 3D screens thread shortly on my thoughts on the 5D and some other screen materials I looked at.

W. Jeff Meier in his Screen material test report pretty much nails the 2D performance description for the 5D - color reproduction is excellent, it has a very smooth surface and you do get some shimmer due to the reflective elements in the screen. IMO any screen with gain has hotspotting and this is a silver screen with gain and reflective elements so it's definitely not a 'clean' 2D screen. I have an HP 2.4 Da-Lite screen as well for comparison and while that's a better screen for 2D from a 'clean' reflective elements perspective, the color reproduction isn't as good as that on the 5D.

For 2D I only use one projector which is set in ECO mode and I have the white level turned down to 13ftl from about 17-18ftl. Having one lamp age differently isn't an issue as I can recalibrate as time goes on with the Radiance units\Calman and both projectors will still match in their light output and color balance.

i think the easiest way to get riddof hotspotting is go curved.
Had for a while but dropped it down while i was waiting my omega filtters. I might Try it one more time maby some time if there comes superbly better silverscreens. Im bothered about the ghosting every silver seems to have, atleast based on samples compared to one i have.
Curved screen is pretty easy to do if you get yourself some metal/aluminiumin to make a frame and use some threaded
Rod on top and bottom attached to the screen material, just tie from the Sail holes if you have them on your screen material.
Then have some stoppers at left and right top and bottom of the frame at the screen edge level to force the threaded rod to bend backwards. Just have the frame mounted off the wall 20-30 cm with some shelf holderit so there is room for bendings.
After maskin the tie strings of the screen it even looks great and if and just if you wanna use backlight its easy to light some at the Back of the screen course its not that fixin.
Worked like charm, i loved it.
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post #2312 of 2321 Old 02-15-2015, 10:07 PM
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Quote:
Originally Posted by Vaan Janne View Post
i think the easiest way to get riddof hotspotting is go curved.
Had for a while but dropped it down while i was waiting my omega filtters. I might Try it one more time maby some time if there comes superbly better silverscreens. Im bothered about the ghosting every silver seems to have, atleast based on samples compared to one i have.
Curved screen is pretty easy to do if you get yourself some metal/aluminiumin to make a frame and use some threaded
Rod on top and bottom attached to the screen material, just tie from the Sail holes if you have them on your screen material.
Then have some stoppers at left and right top and bottom of the frame at the screen edge level to force the threaded rod to bend backwards. Just have the frame mounted off the wall 20-30 cm with some shelf holderit so there is room for bendings.
After maskin the tie strings of the screen it even looks great and if and just if you wanna use backlight its easy to light some at the Back of the screen course its not that fixin.
Worked like charm, i loved it.
I just posted in the Screens for 3D projection thread on my testing from a few different materials. The $5 DIY screen I outline there might make an interesting test to compare to your existing silver screen material and polarization retention.

Hotspotting - that's an interesting subject in itself. How wide is your screen (left to right) and how many multiples away from the screen do you have the PJs mounted? Are the PJs mounted at the top of the screen or below the top edge of the screen? My PJs are mounted more than 2x the screen width from the screen surface.
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post #2313 of 2321 Old 02-16-2015, 08:42 AM
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Quote:
Originally Posted by Vaan Janne View Post
i think the easiest way to get riddof hotspotting is go curved.
Had for a while but dropped it down while i was waiting my omega filtters. I might Try it one more time maby some time if there comes superbly better silverscreens. Im bothered about the ghosting every silver seems to have, atleast based on samples compared to one i have.
What sreens did you have? I am considering linear polarization on this one: http://screenresearch.com/website/do...eb_01_2013.pdf as it has quite small holes for audio transparency. I wanna go 4k & curved.
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post #2314 of 2321 Old 02-16-2015, 10:02 AM
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What sreens did you have? I am considering linear polarization on this one: http://screenresearch.com/website/do...eb_01_2013.pdf as it has quite small holes for audio transparency. I wanna go 4k & curved.
I had Custom made. Wax canvas painted with silver paint from awater 3D
To my experience it was pretty smooth, not so much grainy as many silver materials at 2D.

I did order many samples. Dalite ect best 3d canvases and i think the polarisation retention was as **** on these samples as in my Custom screen. I gues its ok on many movies but after watching the omega filtters the 3D effect is still so much sharper than polarized, because of the noin ghosting filtering technik.allthough i miss the color accuracy of polarized.Point of my reply is i did not find a bit worth the money to spend on expensive professional screen materials because my personal opinnion is they Were not a bit better and cost a joke.

Last edited by Vaan Janne; 02-16-2015 at 10:14 AM.
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post #2315 of 2321 Old 02-17-2015, 02:50 PM
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Top screens like Steward 5D claim over 90% of polarization retention though. Well, and I am not sure If I can live with the color inacuracy of the Omega filters, that's why I want to go polarized.
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post #2316 of 2321 Old 02-17-2015, 05:16 PM
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Originally Posted by zorg43x View Post
What sreens did you have? I am considering linear polarization on this one: http://screenresearch.com/website/do...eb_01_2013.pdf as it has quite small holes for audio transparency. I wanna go 4k & curved.
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Top screens like Steward 5D claim over 90% of polarization retention though. Well, and I am not sure If I can live with the color inacuracy of the Omega filters, that's why I want to go polarized.
I am thinking of the same thing. I spoke to the Stewart's distributor here in Australia and he was quite knowledgable in the passive 3d setup. I am wanting to do a 2.35 screen and he basically said that I would get a much better result with a curved screen.

The only issue with 4k is you are restricted to three companies with licensing - Sony, Christie and Barco. I had a look at Barco and Christie, they really don't have anything that is really fit for home use. That leaves Sony the only option. From most tests they the Sony's Red/Blue is going to be at 90 degree with the green making it less efficient than a JVC which is of course not really a 4k. However, there are virtually no 4k content at the moment so the JVC e-shift may give you the a close result to a Lumigan upscaled 4k image at a much lower price.

At the moment, I am incline to wait until 4k is cheaper. The extra 20k on the projector is better spent on the A-lens.
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post #2317 of 2321 Old 02-20-2015, 12:59 PM
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Like you said, it is better to wait until there are more 4k or UHD pjs available. The few Sonys there already available are still quite pricy and have quite a disadvantage - low speed HDMI. But on the other hand they're true 4k, not only UHD. I bet for the next generation of their pjs they choose different native resolution of the panels not to interfere with the professional segment.
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post #2318 of 2321 Old 02-23-2015, 04:18 AM
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Quote:
Originally Posted by zorg43x View Post
Top screens like Steward 5D claim over 90% of polarization retention though. Well, and I am not sure If I can live with the color inacuracy of the Omega filters, that's why I want to go polarized.
Measuring polarisation retention in percentage give a very poor representation of what will happen.
Screens for polarised 3D must have more than 99% polarisation retention, all these screens will fit within the last 1% but any extra decimal point will have a huge impact on screen.
In order to get a proper idea of how well it looks that value should be measured as an extinction ratio = correct polarisation / incorrect polarisation. Because that will almost be the actual amount of crosstalk you'll get (the screen is the weakest link in the chain).
Typical polarisation filters have extinction ratios above 1000:1, but screens range between 80:1 (poor screen) and 150:1 (excellent screen)

The last time I checked, Stewart provides charts on their website showing how the extinction ratio varies according to the view angle.
Edit : It seems I can't find the charts on their new website
Edit 2 : I checked harkness screens' website to see what the competition does, it looks like they went the other way, they made a higher gain, lower view angle screen but with a crazy high 270:1 extinction ratio (Spectral 300). That screen would be unusable with a flat screen, a curved screen would be mandatory with such a beast.

Passive 3D, forever !
My Full-HD dual-projector passive polarised 3D setup. (really out of date ! I need to update it some day...)


Last edited by BlackShark; 02-23-2015 at 04:38 AM.
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post #2319 of 2321 Old 05-06-2015, 05:42 AM
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Originally Posted by BlackShark View Post
Measuring polarisation retention in percentage give a very poor representation of what will happen.
Screens for polarised 3D must have more than 99% polarisation retention, all these screens will fit within the last 1% but any extra decimal point will have a huge impact on screen.
In order to get a proper idea of how well it looks that value should be measured as an extinction ratio = correct polarisation / incorrect polarisation. Because that will almost be the actual amount of crosstalk you'll get (the screen is the weakest link in the chain).
Typical polarisation filters have extinction ratios above 1000:1, but screens range between 80:1 (poor screen) and 150:1 (excellent screen)

The last time I checked, Stewart provides charts on their website showing how the extinction ratio varies according to the view angle.
Edit : It seems I can't find the charts on their new website
Edit 2 : I checked harkness screens' website to see what the competition does, it looks like they went the other way, they made a higher gain, lower view angle screen but with a crazy high 270:1 extinction ratio (Spectral 300). That screen would be unusable with a flat screen, a curved screen would be mandatory with such a beast.
spectral 300 has smoothest shimmering than any of their polarized screens...atleast i think so.
Blackshark Do you think i have problem with hotspotting ?
i have manual iris in HC5 so i can close it to ridicilously dark. and i got a curved frame
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post #2320 of 2321 Old 05-08-2015, 08:52 AM
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If you want to go with a silver screen I suggest MDI strong. In the screen section I did a review of their StereoView screen. They are a screen company for the commercial theaters but can make you a smaller screen, I made my own frame. They also have a screen called HighWhite which is supposed to be even better with less sparkle and a better 2D viewing.
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post #2321 of 2321 Unread Today, 02:23 PM
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After 4 years of good and loyal services, I am looking for a replacement for my silverscreen.
The Harkness Spectral240 screen material has very good polarization retention capabilities, but it has big flaws :
-it has a high gain, and narrow view angle, creating a hotspot of very intense light in the middle, with a sharp light drop near the edges
-it's has a visible grain that make the picture look blurry, it's designed for large cinema screens, not for close-up use in the home, making it unacceptable for 2D use in the home
-it has a very strong shimmering due to the aluminium flakes embedded in the screen material's surface

I looked for better options. There are a few other silverscreen manufacturers out there that have silverscreens designed to be more balanced for 2D and 3D.
But one screen grabbed my attention : Screen Innovation's BlackDiamond 2.7 gain (the others don't keep polarization properly).
It's not a silverscreen, but it's a special material that has ambient-light-resistant properties. The 0.8 and 1.4 gain versions preserve polarization partially, but not well enough for 3D. The 2.7 gain screen is claimed to work well for polarized 3D, and I remember reading rdjam saying he owns one and it works well.

There is just one problem : I can't find good retailers in my country, and in the only shops I do find, it's expensive as hell !

Out of pure luck only google can provide, I found out about a small competitor I had never heard about : Xtrem Screens (and for good reason, their website is not done, they just provide a contact email)
I found about them by reading a french AV forum talking about their ambient-resistant screen, the Xtrem Screen Daylight. It turns out there is a thread here at AVS about this screen with all the right links and pictures Xtrem Screen Daylight cheaper alternative to the black diamond : User review
I wondered if by trying to reach the same goal, they might use the same process (by creating a similar screen to BlackDiamond, they might produce a good screen for polarised 3D).

I contacted them, and had a lengthy discussion with one of their technicians (I believe he is one of the founders of the company).
It turns out had a good intuition !

-Xtrem Screens Daylight ambient-light-resistant screens do maintain polarization
-it was part of the design, not a fluke
-they have had clients who tried polariszd 3D with it and they said it works
-their Daylight "reference" 1.1 gain screen is the best they offer for polarized 3D
-their Daylight 0.9 gain screen also works, but does not maintain polarization as well as their 1.1 gain screen
-an other Daylight 1.4 gain screen exists (it's the one shown in the screens at the link above), it was their first model, but they only recommended their newer 1.1 and 0.9 models, which they claim are significantly better.
-they make their screens with standard fixed frame, super-slim "zero edge" style frame, and also have a motorized rollable version
-it's still an expensive screen, but it's half the price of the Black Diamond (at least in my country)
-they are very confident in their product, they claim it's better than the Black Diamond, and are ready to offer me a full refund if I'm not happy with it
-their office in my country, near Strasbourg, a city I visit very often (Alsace power !)

I am going to give their screen a try

Passive 3D, forever !
My Full-HD dual-projector passive polarised 3D setup. (really out of date ! I need to update it some day...)


Last edited by BlackShark; Today at 02:41 PM.
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