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Discussion - Screens for 3D Projection

132K views 366 replies 99 participants last post by  rithu 
#1 ·
This thread is intended for the discussion of projection screens for use with 3D front projectors. It is not intended to be focused on just one brand or model of 3D ready front projector, but rather is to be focused on the desirable characteristics for projection screens that will be used with such 3D projectors and to report on the testing and experiences with different available projection screen models and projection screen fabrics. It is not my intent to duplicate the general discussions on projections screens found in the existing Screen Forum here on AVS. Rather the focus here needs to be on the unique projection screen issues and characteristics required for good performance when used for the projection of 3D.


I will be updating the information in this post as I collect additional information on this topic.


There are some additional factors that need to be considered in selecting a suitable projection screen for 3D viewing in a home theater environment as compared to limiting the screen considerations to only supporting conventional 2D viewing. First you need to know what technology your 3D projector uses to separate the projected right and left images. This can either be by the projector using a different polarization of the projected light for the left and right images and the viewer wearing polarized 3D eyeglasses (sometime called passive glasses since they contain no electronics) -or- the projector can alternate the left and right images (while not changing the polarization of the light) and the viewers are required to wear liquid crystal shutter 3D eyeglasses (sometimes referred to as active glasses since they contain electronics). The next most important factor that must to be considered when selecting a screen is the image brightness (i.e., the actual level of the light reaching the viewer's eyes) with a typical 3D projection systems is as little as 15% of what you would get for 2D viewing using the same projector, or a similar 2D only projector. Because of this substantially dimmer projected 3D image (including the potentially reduced lumens of light output from the projector when operated in 3D mode plus the inherent light loss through the 3D eyeglasses), factors such as screen size, screen gain and in some cases, the ability to retain polarization of the light need to be considered when selecting the most appropriate screen. It is generally considered acceptable in commercial cinemas for 3D viewing to have lower light levels than what is considered suitable for conventional 2D movie presentations. In the home theater environment, most viewers will also except a dimmer image for 3D viewing. However, selection of the appropriate projection screen can at least be partially compensate for the lower effective lumens from the 3D projection system (i.e., projector plus eyeglasses).


Generally the requirements for projection screens suitable for the projection of 3D video will fall into two broad categories as listed below. The first category of screen is suitable for use with 3D projectors for which viewers must wear liquid crystal shutter (active) eyeglasses for viewing 3D programs. The second category of projection screens listed below is required for use with 3D projectors that require viewers to wear polarized (passive) 3D eyeglasses for view 3D programs.
  • Screens that retain none or only partial polarization of the projected light
  • Screens that retain near full polarization of the projected light

Screens that retain none or only partial polarization of the projected light

This broad category of projection screens are suitable for use with 3D projection systems that sequentially alternate the right and left images and for which viewers are required to wear liquid crystal (LC) shutter eyeglasses for viewing 3D programs. Most currently available and announced consumer 3D projectors are compatible with this category as projection screen as they do not require the projection screen to retain polarization. This includes such low-end 720p DLP 3D projectors as the Optoma HD66 , Viewsonic PJD6531w and Acer H5360 and well as available or announced mid-to-high level 1080p 3D projectors from JVC (DLA- RS40 , RS50 , RS60, X3, X7 and X9), Sony (VLP-VW90ES) , and Mitsubishi HC9000 .


As mentioned above, 3D projectors compatible with this category of projection screens includes the 3D-ready LCoS based 1080p projectors from JVC, Sony, Mitsubishi and any of the "3D ready" 720p DLP projectors from companies such as Acer, Optoma, etc. While such 3D projectors can technically be used with any conventional projection screen that works for 2D, there are a few additional factors that come into play when you want to also have an optimal 3D viewing experience (in particular having an adequately bright image). The SMTPE industry standard for conventional 2D projection cinema recommends image brightness levels, as measured off of the screen, of 12 to 22 footlamberts (ftL) with 16 ftl being a nominal value - Reference Here . For 3D presentation it is generally believed that a lower image brightness is acceptable and effective brightness levels on the order of 5 ftl, with the light loss thru the required 3D eyeglasses are also factored in, are not uncommon, but not necessarily ideal, in commercial cinemas. The home theater 3D projection systems using LC shutter eyeglasses typically provide only 15% to 20% as much light that actually reaches the viewer's eyes, as compared to using the same projector in 2D mode and viewing without the LC shutter eyeglasses. As a result, if the home theater system provides a near ideal 16 ftL of brightness for 2D viewing it may only provide a rather dim 3 ftL (or less) in 3D mode. The following factors should be considered when selecting a screen intended to support 3D (as well as 2D) projection in your home theater.
  • Screen Gain - Some screen materials can provide a positive ' gain ' as compared to a reference pure white matte screen surface (with a reference gain of 1.0). Selecting a higher gain screen can be a help in offsetting the light loss inherent with 3D projection systems. However, when considering higher gain screens (i.e., with gains of 1.5 or more) one must also consider the more limited viewing angle supported by such screens. Read HERE for a good overview of screen gain. The Da-Lite screens using their "Highpower" screen material are probably the most popular high gain screen among AVS forum members. These screens are 'retro-reflective' and for maximum gain require the projector be mounted near eye-level and have a relative narrow viewing cone which may or may not work for a specific home theater configuration.
  • Screen Size - Bigger isn't always better when it come to screen size. For a given projector and screen material doubling the screen size (e.g., going from an 80 inch to a 160 inch screen) decreases the image brightness by 75%. Using a more modest screen size for a home theater where 3D projection will be used is one approach to accommodating the greater light loss inherent with 3D projection systems.
  • Ability of the Screen to Retain Polarization of the Light - While 3D projection systems that rely on LC shutter eyeglasses do not rely on polarization to separate the right and left images, the ability of a given screen material to retain polarized light can be a factor that effects the overall image brightness. This occurs if the projector is using LCoS or LCD technology (i.e., not applicable to DLP 3D projectors). These technologies inherently project light that is polarized. Note that no projection screen can change the orientation of the polarization of the light that is coming from the projector, thus the screen can at most retain some of polarization of the light coming from the projector. For example, the new JVC 3D projectors project a horizontal polarized light. Also the LC shutter eyeglasses inherently include a polarizing element, which in the case of the JVC LC shutter eyeglasses are also horizontal polarized. If the projection screen retains none of the polarization of the light (i.e, actually the light reflected off the screen becomes randomly polarized), then the polarizing element within the eyeglasses will filter out approx. 50% of the light. On the other hand if the screen were to fully maintain all of the polarization then using shutter eyeglasses that have the same orientation for the polarization as the projector will result in less light loss within the eyeglasses and thus will present a brighter image to the viewer. So if your are using a LCoS projector with a projection screen that retains any significant polarization of the light from the projector, then it is important to use LC shutter eyeglasses that have the same polarization as the projector. Check out THIS POST for test results that directly show the benefit of using a screen that retains polarization with LCoS projectors.

Screen manufacturers sometimes publish an "extinction rate" or "extinction ratio" which is a measure of the ability of a given screen material to retain the polarization of the projected light. They will normally only provide this for screens intended for use with polarized 3D projection systems.


Below are preliminary results from testing of several screen materials that indicates the extent to which each screen material retains the polarization of the light.Note: The use of 'universal' 3D liquid crystal shutter eyeglasses that have the opposite orientation for their polarization as compared to the projector will result in additional light loss. Therefore, if using a screen with a higher polarization rating (e.g., 2 or more in the table below) it is recommended to select eyeglasses with the same orientation of the polarization as used by the projector. This should always be the case if you use the eyeglasses from the same manufacturer as the projector. An example of eyeglasses and projectors having the opposite polarization orientation is the Xpand X103 universal 3D glasses which have vertical polarization and the JVC RS40, RS50, RS60 series of 3D projectors that have horizontal polarization.

Polarization Rating (see notes below):\t

0 - no or slight visible polarization - perhaps 0% to 15%

1 - a very small amount of visible polarization – perhaps 15% to 25%

2 – moderate level of polarization observed – perhaps 25% to 40%

3 – significant level of polarization observed – perhaps 40% to 60%

4 – high level of polarization observed – more than 60%
Manufacturer/Fabric..........................Rated Gain..........Polarization.Rating


Carada/Classic Cinema White.............................1.0..........................2


Carada/Bright White.........................................1.4................ .........0.5


Da-lite/HD Progressive 0.6.................................0.6........................ .0


Da-lite/High Contrast Audio Vision.......................0.8..........................1


Da-lite/High Contrast Da-Mat.............................0.8..........................1


Da-lite/HD Progressive 0.9.................................0.9........................ .0


Da-lite/Matte White.........................................1.0................ .........0


Da-lite/Da-Mat................................................1.0......... ................1


Da-lite/Audio Vision..........................................1.0............... ..........1


Da-lite/HD Progressive 1.1.................................1.1........................ .3


Da-lite/High Contrast Cinema Perf.......................1.1..........................4


Da-lite/High Contrast Matte White......................1.1..........................2.5


Da-lite/High Contrast Cinema Vision....................1.1...........................4


Da-lite/Cinema Vision.......................................1.3.................. ........4


Da-lite/Video Spectra 1.5.................................1.5........................ ..4


Da-lite/Pearlescent.........................................1.5................ ..........3.5


Da-lite/High Power..........................................2.4............... ............0


Da-lite/High Power..........................................2.8............... ............0


Dragonfly/High Contrast...................................?........................ ......0


Elite/Powergain..............................................1.8........... .................4


Elite/Cinewhite Tensioned Matte White...............1.1.............................1


Elite/High Contrast Grey Tensioned....................1.0.............................1


Focupix/Matte White (used on tensioned electric).1.4............................1


Screen Innovations/Black Diamond II..................1.4............................4


Screen Innovations/Solar HD.............................1.3...........................0


Screen Research/ClearPix 2...............................1.0.......................... 0


Seymour/Center Stage XD................................1.2......................... ..0


Stewart/StudioTek 100....................................1.0..................... ......0


Stewart/StudioTek 130 (older version)................1.3...........................4


Stewart/StudioTek 130 G3...............................1.3.......................... .2 (?) note 3


Stewart/StudioTek 130 G3 Microperf..................1.3............................0


Stewart/UltraMatte 150....................................1.5..................... .....2 (?) note 3


Stewart/Firehawk (original version).....................?.............................4


Stewart/Firehawk G3.......................................1.25................. .......4 (?) note 3
Notes:


1. These results come from observations/results posted by multiple forum members and as a result the "polarization rating" is my best effort to align the observations of these multiple forum members to a common basis for comparison.


2. As the light source, these tests used a video projector that produced a linear polarized video image. The estimates expressed as a percentage are based on the difference in brightness when viewing a given screen through a linear polarizing filter with it oriented to produce the brightest image vs. the dimmest image. The above results only apply for linear polarized light and these results do not indicate the ability of a given screen material to retain circular polarization. The above results would represent the relative difference in brightness of using LC shutter 3D glasses with a linear polarizing element that correctly matches the orientation of the polarized light from the 3D projector vs. using LC shutter glasses with the wrong orientation for the polarizing element (i.e, orientation shifted 90 degrees). If you compare two screens with identical gains for normal 2D viewing but where one retains some of the polarization and the other one does not, a 3D image projected on the screen that retains some polarization will be brighter when viewed using LC shutter glasses with the correct polarization orientation. However, if the value listed in the table above shows a "polarization rating" of 3, indicating approx. a 50% relative difference in brightness between being viewed through LC shutter glasses with the correct vs. wrong polarization orientation, then the viewer can expect that screen to produce an image that is perhaps 25% brighter than if viewed on another reference screen with the same rated gain but that does not retain any polarization. This is only an approximation since we do not yet have actual measurements made under controlled test conditions that can be used to quantify the increase in brightness as a direct result of the level of polarization being retained by a specific screen surface.


3. There is a recent report (July 2011) that the latest version of the Stewart ST130 retains almost no polarization. It appears that this, and perhaps other Stewart screen materials including the Firehawk, have undergone changes in 2011 that reduced the level of polarization they retain. Bottom line is do not assume that a newly purchased Stewart screen, other than those 'silver screen' fabrics that are specifically sold for 3D (see below), will retain very much of the polarization.

Screens claimed to retain full (i.e., close to 100%) polarization

This category of projection screens are suitable for use with 3D projection systems that use polarization as the method to separate the right and left images and where the viewers wear eyeglasses with polarized lens, each with a different orientation. The only consumer 3D projector announced yet that requires a screen that preserves polarization is the LG 3F3D (MSRP approx. $15,000 USD). This projector essentially combines two imaging light engines within a single case and projects the right and left images using a different orientation for the polarization. There are also some high-end "prosumer" ($50,000+) setups that also require polarization preserving screens. These high-end systems either use dual projectors (i.e., using two 2D projectors plus a processor) or a single projector plus an electronically controlled polarizing filter that alternates between two different polarization orientations with each consecutive video frame. Finally there are do-it-yourself setups possible using dual low-to-mid-level consumer 2D projectors plus external processor(s) or a properly equipped PC. HERE is a thread by an AVS forum member describing their DIY dual projector, passive polarized 3D projection setup.


Let us now consider projection screen surfaces that are suitable for use with 3D projectors that use polarization to separate the right and left images. Such screens must maintain near to 100% of the polarization of the light being projected, otherwise crosstalk (i.e., ghosting) between the right and left images will result. Traditionally a screen with a silver surface was used for polarized 3D projection systems and such screens are available from several sources including DaLite, Harkness and Stewart. However, silver screens tend to perform poorly for conventional 2D applications because their highly reflective surfaces tend to produce "hot spotting" (e.g., image noticeably brighter in the center as compared to the edges) and a fairly limited viewing cone (i.e., viewers need to be seated more directly in front of the screen). As a result when such silver screens are used in a home theater it is not uncommon to install a second screen more suitable for 2D viewing. For example, a fixed frame silver screen screen could be attached to the wall for 3D viewing plus an electric drop down screen for 2D viewing could be mounted just in front of the fixed frame screen. With the recent consumer interest in 3D systems for use in their home theaters, a few screen manufacturers have either announced, or are believed to be developing, new screen materials that are intended to offer more acceptable 2D performance while still retaining polarization as necessary for 3D viewing. Stewart has announced a new silver screen material called 5D (ie., 2D + 3D = 5D) - information is HERE . Screen Innovations' Black Diamond II screens are said by the manufacturer to retain polarization as necessary to support passive 3D projection solutions, but tests conducted by one AVS Forum member have found they will not retain enough of the polarization (i.e., measured at only about 65%) to be considered viable for for use for 3D polarized projection systems - see results for other screen materials below.


Screen manufacturers sometimes publish an "extinction rate" or "extinction ratio" which is a measure of the ability of a given screen material to retain the polarization of the projected light. They will normally only provide this for screens intended for use with polarized 3D projection systems.


AVS forum member rdjam has tested the following screen materials for their ability to retain linear polarization and reported the results as listed below:
Manufacturer/Fabric-------% of Linear Polarization Retained

Stewart/3D-----------------91%

Stewart/5D-----------------87%

Dalite/Silver Matte----------85%

Dalite/3D Virtual Grey-------81% to 82%
For 3D projection systems using linear polarization to separate the right and left video streams, the best of the above screens (with near 90% retention of the polarization) are adequate, but still not ideal, to minimize the visible crosstalk (i.e, ghosting). Also be aware that with linear polarization based 3D systems, when the viewer tilts their head, even just a few degrees toward the side, the crosstalk will become more obvious.


While there may be screen materials that retain linear polarized light to the extent necessary to keep crosstalk (ghosting) down to acceptable levels (see above), circular polarization is an entirely different matter. AVS forum member rdjam has also tested the following screen materials for their ability to retain circular polarization and reported the results as listed below:
Manufacturer/Fabric-------% of Circular Polarization Retained

Stewart/3D-----------------80 to 81 %

Stewart/5D-----------------77%

Dalite/Silver Matte----------77%

Dalite/3D Virtual Grey-------70%
He reported that none of the above screens materials are able to retain circular polarization adequately to eliminate visible crosstalk (ghosting) between the projected right and left image streams. So at this point no screen material has been verified to be considered acceptable for use with a 3D projection system that employs circular polarization to seperate the right from the left image screens.


Dalite has recently announced a new screen material called Silver Lite 2.5 that is described by Dalite as:
A multi-purpose front projection surface that is optimized for passive linear and circular 3D applications and is also an excellent 2D screen material. For passive 3D applications, the silver surface maintains 99.3% of polarized light and the 2.5 gain of the material compensates for the light lost in the polarization filtering process. The polarization retention and high extinction ratio eliminate the ghosting or crosstalk common with stereoscopic 3D projection.

HERE is a tutorial on the use of polarized light for 3D projection.

HERE is a link to a web site that discusses the available silver screens for use in 3D projection.


Screen Manufacturers
  • Focupix (distributed by HT Depot)

Projection Calculators


The attached zip file (see below) is a simple Excel spreadsheet I have prepared for estimating 2D and 3D image brightness given a user specified screen size, screen gain, ability of the screen to retain polarization and projector lumens output. For 3D projectors that project polarized light, this calculator assumes the 3D eyeglasses have the same orientation for the polarization as does the projector. The increase in effective 3D screen gain, and thus image brightness, that results from using a screen that retains some polarization, as provided by this calculator should only be taken as a rough estimate.

HERE is a link for a much more detailed 2D projection calculator that was developed by AVS Forum member FLBoy. Also Projector Central has an online 2D calculator for specific brands and models of projectors ( HERE ). Note these latter two calculators are for 2D projection as they do not account for the light loss associated with the 3D projection and viewing.

 

Simple Projection Calc.zip 3.9580078125k . file
 

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#2 ·
Great thread to start. I am expecting my JVC DLA-RS40 projector soon and would greatly appreciate suggestions on the best kind of screen to purchase to use with this projector. I am pretty much new to projectors as this will be my first projector owned so I am not experienced in this matter.
 
#4 ·
After watching a handful of 3d films on my new 2.8 HP (I am getting ~2.1 gain at my center seat subjectively AND according to Flyboys calculator, and a bit less on the ends of my couch), I am impressed vs my ST130, but definitely not a night/day difference. The difference is certainly noticeable in 3d vs the 130, but considering I am getting ~2.1 out of the HP, the fact that the 130 is maintaining some polarization and is a true 1.3 gain, and the relatively low 3d ftL in general through the glasses, the dif does not seem as dramatic as what I witnessed viewing 2d material. In order for the polarization preserving ST130 to get up to the brightness level of the non polarizing HP at the ends of my couch, I would say the ST130 would need to be ~1.6-1.7 gain...............at my center seat it would take a polarization preserving ST130 to be ~2.0 gain. Dont get me wrong, this is easily noticeable when I brought my ST130 back in my room and hung the HP 2.8 sample on it, but when you put the glasses on it is not quite as dramatic as seeing the comparison in 2d with the glasses off and I am betting the fact that the 130 retains some polarization vs the HP which essentially retains none is the big reason.


Having said all that, and again this is subjective and I did not try to take any measurements, the great thing is that on the ends of my couch I can get ~the same brightness with my HP screen as compared to my ST130 screen but at the same time closing down the aperture ~-8 clicks. In the middle, the increase is even more. SO, at least I have gained some headroom as the lamp ages with the new HP if nothing else, and in the center seat I am still getting a bit brighter pic while also having the aperture closed down from where it was with the 130. So all in all, The HP still has a very nice advantage for 3d vs my 130.


EDIT: Just to make note, I am using the JVC horizontally polarized glasses and the newer ST130 G3 material in my tests.
 
#6 ·

Quote:
Originally Posted by jbolt /forum/post/19745275


Sorry if this has already been answered, but I am new to this board after I purchased my first projector which is the JVC DLA-RS40. It should arrive next week and I hear people on here talking about the Da-Lite High Power 2.8 gain screen. I am in the market to buy a screen, so my question is where is the best place to view and possibly purchase this screen?

The manufacturer's website is http://www.da-lite.com/ .

A great source of information is http://www.avsforum.com/avs-vb/showthread.php?t=773065 .

You can order Da-Lite screens from the AVSForum sponsors: https://shop.avscience.com/crm.asp?action=contactus .


Note that there are two HP fabrics - a 2.8 gain and a 2.4 gain. You can order samples from Da-Lite to see which you prefer.


FLBoy's screen gain calculator can also help determine which material is better suited for your room layout: http://www.avsforum.com/avs-vb/showthread.php?t=966057 .
 
#7 ·
Ron - thank you for starting this thread. It was really needed and will be a great resource (and already is actually). It is very disappointing that I cannot use the Xpand glasses with the JVC RS series because not only are they cheaper, but I have another 3D display (Samsung plasma) which works fantastic with the Xpands.
 
#9 ·
For shutterglasses, any screen will work, and the more gain the better. For 100% polarization it's always been about how much metallic material is in the paint. The silvered screen is still king for polarized 3D in my estimation and only a few manufacturers make it.
 
#10 ·

Quote:
Originally Posted by threed123 /forum/post/19746302

For shutterglasses, any screen will work, and the more gain the better. For 100% polarization it's always been about how much metallic material is in the paint. The silvered screen is still king for polarized 3D in my estimation and only a few manufacturers make it.

See post #1 above. If you are using a LCoS (e.g., DILA, SXRD) 3D projector the light from the projector is polarized (even though they are not using polarization as the means to separate the right and left images) and if the screen material maintains any significant amount of that polarization then using shutter glasses (which inherently have a polarizing filter element) that have the same orientation for the polarization as the projector will produce a brighter image than using shutter glasses with a different orientation. Also when using shutter glasses with the same polarization orientation as the projector a screen that maintains a significant amount of the polarization will produce a brighter image for the viewer than another screen with the same gain that loses all of the polarization. This is due to less light loss thru the 3D glasses. So the bottom line is the ability of a screen to maintain polarization can make a difference with projection systems using LCoS projectors and liquid crystal shutter glasses. It is not applicable to DLP projector based 3D systems because these projectors do not produce polarized light.
 
#12 ·
Go to the Da-Lite website instead ( http://www.da-lite.com/products/ ). Then figure out if you want fixed or pull down. If you go fixed any of the top three selections will get you close to what you want. When you pick one of these three it will open up another page. Go to the parts and pricing section. This opens up another page. Scroll down until you find out what you want in screen formats (video, HDTV, etc.). You then scroll down until you find your size and then look for the model numbers with High Power. Once you figure out what type of frame, screen format and size it will make you looking for a screen easier. Right down the model number and when you go to a particular website search for that number.


When you decide what you want check with AVS for the pricing. I did find a few websites that was cheaper than AVS, but I knew from experience that if something was wrong AVS would make it right.


Edit: Do not pay attention to the cost shown on the Da-lite website - the screens are considerably lower than posted as "suggested retail".
 
#13 ·
Quote:
Originally Posted by Ron Jones
(This)... is not applicable to DLP projector based 3D systems because these projectors do not produce polarized light.
This important fact needs to be stated clearly at the very beginning so consumers can avoid all these conflicting issues by simply selecting DLP technology. Trouble is DLP can today only handle 1280 3D resolution, not 1080p.


To simplify polarized liquid crystal systems have many more obstacles to overcome as compared to non-polarized plasma and DLP. Expensive gear for one system may not work in another. For best performance, 2D screens should to be different than for 3D.


Two Strategies:

1) buy non-polarized plasma 3D for daytime (or smaller 65" screens) and go with the $600 1280 3D DLP front projectors. Then wait for TI to release a 1080p 3D chip. The same optimal screen can serve both 2D and 3D.


2) otherwise buy stock in the projection screen companies ($4K for 2D screen + $6K for 3D screen) then whine about optimizing your system to display the LCD 3D ghosting artifacts.


Great post and great logic. Thank you!
 
#14 ·
Quote:
Originally Posted by HiFiFun
This important fact needs to be stated clearly at the very beginning so consumers can avoid all these conflicting issues by simply selecting DLP technology. Trouble is DLP can today only handle 1280 3D resolution, not 1080p.


To simplify polarized liquid crystal systems have many more obstacles to overcome as compared to non-polarized plasma and DLP. Expensive gear for one system may not work in another. For best performance, 2D screens should to be different than for 3D.


Two Strategies:

1) buy non-polarized plasma 3D for daytime (or smaller 65" screens) and go with the $600 1280 3D DLP front projectors. Then wait for TI to release a 1080p 3D chip. The same optimal screen can serve both 2D and 3D.


2) otherwise buy stock in the projection screen companies ($4K for 2D screen + $6K for 3D screen) then whine about optimizing your system to display the LCD 3D ghosting artifacts.


Great post and great logic. Thank you!
I don't agree that for non-DLP based projectors that use LC shutter eyeglasses you cannot have a single screen that works well for both 2D and 3D. It's just that anyone creating a home theater using an LCoS projector (or LCD if there ever is one that supports 3D) should take into consideration one additional factor in the selection of the screen (does it retain significant polarization or not). There are screens that will work well for both 2D and 3D with such projectors, but the owner may also need to match the polarization orientation of the LC shutter eyeglasses with that of the projector. However, for any 3D projection technology that uses polarization to separate the right and left images then I do agree that screens that work well for 3D will not be ideal for 2D projection.
 
#15 ·
Good post. Should be stickied as we're starting to see Sony and JVC 3D LCoS projectors hitting the market. Wondering when SMPTE, THX or some other group will publish 3D standards for minimum light level, percentage of crosstalk, viewing distance, etc.


Also, another thing I've noticed between viewing 3D in the daytime on a flat panel vs 3D projected in a light controlled room is that you miss some visual cues for determining depth. On a tv, you can clearly see the bezel to give you a frame of reference for the objects on the z axis. In a commercial theater, you also have the exit signs or reflections from the audience that provides this. But in a completely black room you don't really have those visual cues. Are there room guidelines for 3D projection?
 
#16 ·

Quote:
Originally Posted by Toe /forum/post/19745813


After watching a handful of 3d films on my new 2.8 HP (I am getting ~2.1 gain at my center seat subjectively AND according to Flyboys calculator, and a bit less on the ends of my couch), I am impressed vs my ST130, but definitely not a night/day difference. The difference is certainly noticeable in 3d vs the 130, but considering I am getting ~2.1 out of the HP, the fact that the 130 is maintaining some polarization and is a true 1.3 gain, and the relatively low 3d ftL in general through the glasses, the dif does not seem as dramatic as what I witnessed viewing 2d material. In order for the polarization preserving ST130 to get up to the brightness level of the non polarizing HP at the ends of my couch, I would say the ST130 would need to be ~1.6-1.7 gain...............at my center seat it would take a polarization preserving ST130 to be ~2.0 gain. Dont get me wrong, this is easily noticeable when I brought my ST130 back in my room and hung the HP 2.8 sample on it, but when you put the glasses on it is not quite as dramatic as seeing the comparison in 2d with the glasses off and I am betting the fact that the 130 retains some polarization vs the HP which essentially retains none is the big reason.


Having said all that, and again this is subjective and I did not try to take any measurements, the great thing is that on the ends of my couch I can get ~the same brightness with my HP screen as compared to my ST130 screen but at the same time closing down the aperture ~-8 clicks. In the middle, the increase is even more. SO, at least I have gained some headroom as the lamp ages with the new HP if nothing else, and in the center seat I am still getting a bit brighter pic while also having the aperture closed down from where it was with the 130. So all in all, The HP still has a very nice advantage for 3d vs my 130.

Toe,


As you are aware (and for the benefit of others reading this thread), for maximum brightness with polarization retaining screens it is important for people to carefully chose the correct active-shutter glasses type (horizontal vs vertical polarization). If the wrong polarization glasses type is used, then we can expect at least 50% less light to pass through the glasses (50% light discarded by the glasses due to incorrect polarization).


In this regard with the ST130 screen, the JVC horizontally polarized glasses would be appropriate. However, with your HP screen which is a non-polarization retaining screen, either the JVC or ExpanD (vertically polarized) would perform equally but still less affectively/brightly as with the fully polarized selection noted above.


Can you qualify your 3D brightness findings with a note about the type (horizontal vs vertical polarization) of active glasses you used? Also please make a note if your ST130 is the newer G3 material.
 
#18 ·

Quote:
Originally Posted by coolplazma /forum/post/19761307


Toe,


As you are aware (and for the benefit of others reading this thread), for maximum brightness with polarization retaining screens it is important for people to carefully chose the correct active-shutter glasses type (horizontal vs vertical polarization). If the wrong polarization glasses type is used, then we can expect at least 50% less light to pass through the glasses (50% light discarded by the glasses due to incorrect polarization).


In this regard with the ST130 screen, the JVC horizontally polarized glasses would be appropriate. However, with your HP screen which is a non-polarization retaining screen, either the JVC or ExpanD (vertically polarized) would perform equally but still less affectively/brightly as with the fully polarized selection noted above.


Can you qualify your 3D brightness findings with a note about the type (horizontal vs vertical polarization) of active glasses you used? Also please make a note if your ST130 is the newer G3 material.

Good points. I just want to be clear though that even though the 130 retains polarization and the HP does not, the HP was noticeably brighter vs the 130 in every seat on my couch..........the closer you get toward the middle of the couch, the brighter (and the bigger the advantage over the 130) the HP gets, but even in the extreme left and right seats on the couch, it is still brighter than the polarization preserving 130 with glasses on. At the extreme ends of my couch, I would say the polarization preserving 130 would need to be ~1.6-1.7 gain to match the HP............in the center seat, ~2.0 to match the HP...............I am getting ~2.1 or so gain out of the HP according to Flyboys calculator which also corresponds to my subjective viewing.


I made the edit to my post to include the glasses and ST130 info you requested.
 
#21 ·
Great thread!


Based on those measurements, it looks like the ST130 is one of the best in retaining polarization (from the existing list). Makes me wonder if it's worth replacing it with 5D material except maybe for the gain.
 
#23 ·

Quote:
Originally Posted by NavNucST3 /forum/post/19766750


Is there anything extra to consider when looking at acoustic screens?

I don't believe there are any more factors other than listed above, unique for using acoustically transparent screen for 3D projection as compared to 2D projection. Of course such screens do have some unique things that must be considered when selecting one for regular 2D viewing that would equally apply to use for 3D viewing. Perhaps the biggest consideration is to select a fabric that does not result in any moire effect being caused by the weave or pattern of holes in the fabric.
 
#24 ·

Quote:
Originally Posted by Mr Ian B /forum/post/19746286


If someone has a dragonfly and can test and post results would be appreciated. That is what I currently have and could not find much info googling it or owners manual.


Thanks,


Ian B

Spoke with Mark with AVS Store today and did a test on my dragonfly screen and there was no polarization retention. I am good to go with the less expensive 3d glasses.


Ian B
 
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