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A normal user's look into the world of 3D Stereo Technologies

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About the Optimum Viewing Distance of Passive 3D Monitors

February 25th, 2013 · 5 Comments · GeForce 3D Vision

passive-3d-monitor-optimum-viewing-positions


There has been a lot of information what works best and various different recommendations what are the optimum viewing positions of passive 3D monitors, but still a lot of people are having hard time properly adjusting these displays for best stereoscopic 3D experience. There is also a lot of controversy going on around the half vertical resolution you get in stereo 3D mode and the end visual results you get. But with all the recommendations and suggestion what works and what not I ended up doing some testing of my own and decided to present what works best for me when viewing a passive 3D monitor and share this information so it might help others as well. I’ll be using a 23-inch FPR 3D monitor to illustrate this example and that monitor is the Philips 236G3DHSB that I’ve recently reviewed here on the blog. What you should be well aware of is that passive 3D monitors have a very narrow vertical viewing angle when in stereoscopic 3D mode, this angle is usually 5 to 7 degrees up and down, so a total of 10-14 degrees total. Also that when 3D mode is active you get half of the vertical number of lines composing what each eye sees from the total resolution of the display, hence the half vertical resolution of the display. The fact that the the perceived sharpness of the image displayed with half horizontal resolution per eye on a passive 3D display might look better than on a full resolution per eye active 3D display when using Full HD monitors does not necessary mean that both solutions offer the same display resolution in stereoscopic 3D mode. There are many factors that affect how we perceive sharpness of display resolution, but now we are not going to debate these here.

Let us start with a quick look on what various manufacturers of passive 3D (FPR 3D) monitors are recommending as optimum viewing angles and distance for achieving the best experience when using their products in stereo 3D mode. All of the information below is taken form the user manuals of various 23-inch Full HD passive 3D monitors, these are models that the manufacturers decided to publish such information as some manuals do not contain any recommendations at all.

AOC e2352Phz
Sit at a position at least 70 mm (they made a mistake and probably meant 70 cm, not mm!) away from the display unit. Keep the line of sight horizontal to the display unit as far as possible (with the upper and lower angle of view within 10 degrees).

HP 2311gt
For optimal 3D viewing, you should be approximately 60 to 70 centimeters (24 to 28 inches) from the computer display. Depending on the viewing angle, the operational distance from the display can vary.

LG D2342P
The optimal viewing angle of the monitor is 12° in vertical direction while 80° in horizontal direction; the optimal viewing distance is between 50 cm to 90 cm from the monitor. When you view 3D images outside the optimal viewing angle or viewing distance, the images may look overlapped or not be displayed properly in 3D.

Philips 236G3DHSB
For an optimal 3D viewing experience, we recommend that you: Sit at a distance that is at least 55cm; Watch the monitor away from direct sunlight as it may interfere with the 3D experience.

There are no surprises about the viewing angles at all here, we already know they are quite limited and this limit is not affected by the LCD panel type used in the monitor, even an IPS panel won’t help, the limit is caused by the polarizing filter applied over the LCD panel that separates the left and right eye images for stereoscopic 3D use. As for the minimum recommended distance from the 3D monitor we see different numbers from 50 centimeters to 70 centimeters (about 20-28 inches) and as for the maximum recommended distance only LG recommends up to 90 centimeters (about 35 inches). So what works best for me, neither of these recommendations are actually good for me…

A person with normal vision not wearing glasses or wearing the right diopter glasses to correct his vision achieving the same level as what is considered as normal vision would need to sit at about 90-95 centimeters away from a 23-inch passive 3D display (about 35-37 inches) or about 1.5 times the diagonal of the monitor. This minimum distance is required in order for the viewer not to be bothered by the increased distance between the vertical lines that build the image for each eye for stereo 3D content. If your vision is nt good enough to be considered “normal vision” and you wear prescription glasses with 1 diopter you might be able to reduce that minimum comfortable distance to about 75 centimeters (about 30 inches) if you are not wearing your glasses in order not to be bothered by the lines.

Moving up to about just 55 centimeters away from the 23-inch passive 3D displays you will find that this is a the about absolute minimum at which you can get into the correct vertical viewing angle limit and be able to properly perceive volume, but at that distance you will be bothered by the vertical lines building the image you will see. So manufacturers may be right that this is about the recommended minimum, but it is more like the absolute minimum distance and not the most comfortable. Actually the farther you are from the monitor the easier it is to get into the very narrow vertical angle for best results when using the display in stereo 3D mode, but there is a limit to that as well. Going to further away from the monitor will lead to the 3D image starting to look flat thus loosing the stereoscopic 3D effect and the sense of realism provided by the displayed 3D image will further diminish because of the very low FOV coverage your vision will have. Going past about 150 centimeters (about 60 inches) you will start to loose the perception of volume and the image on the screen will start to look flat, not to mention that the immersion factor won’t be that good either because of the screen covering a small part of the vision, but at least it is much easier to get in the vertical viewing angle (at the cost of the reduced perception of sharpness and thus resolution).

The optimal viewing distance of a 23-inch passive 3D monitor for me personally is around 90-100 centimeters (about 35-40 inches), a distance at which I’m not bothered with the vertical lines and the image I perceive is still sharp. At that distance the stereoscopic 3D effect (the sense of volume) is still quite good for various 3D content, and the only drawback that remains is that the feeling of immersion is not that good due to smaller part of the vision covered by the display. And at that distance from the display it is easier to stay withing the optimal vertical viewing angle when you’ve setup the display correctly even with some normal head movements. As a reference to use for a comparison I usually use a 27-inch active 3D monitor in stereoscopic 3D mode at a distance of about 60-70 centimeters for optimal sense of immersion.

If you are using a passive 3D monitor feel welcome to share what works best for you in terms of optimum viewing distance in the comments below.

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Review of the Philips 236G3DHSB Passive 3D Monitor

February 8th, 2013 · 8 Comments · Other S3D Tech

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It is time for another 3D monitor review, this time of the 23-inch Philips 236G3DHSB passive 3D monitor that promises nice 3D features, good performance at an attractive price point. This Philips monitor uses passive 3D technology (FPR 3D) on top of an TN LCD panel withe matte screen not a glossy one, it features two HDMI 1.4 interfaces with support for frame packaged content as well as Side by Side and Over/Under and there is also a built-in 2D to 3D conversion functionality. It seems to deliver what pretty much all other passive 3D monitors offer you, but the real question is what you can expect from the monitor in terms of performance and especially how good it handles stereo 3D content…

Philips 236G3DHSB Specifications:

Panel Size: 23-inches (58.4cm)
Monitor Type: TN TFT-LCD with LED Backlight
3D Technology: FPR 3D Technology
Pixel Pitch: 0.265×0.265mm
Brightness: 250 cd/m2
Contrast Ratio (typ.): 1000:1
SmartContrast: 20,000,000:1
Response Time (typ.): 5ms
SmartResponse Time (typ.): 2ms
Viewing Angles: 170° (H) / 160° (V) @ C/R > 10
3D Viewing Angle: 80° (H) / 12° (V) @ 3D CT < 10
Input: 2x HDMI 1.4, 1x VGA
Power Consumption: On Mode 28.39W (typ.); Sleep (Standby) 0.5W; Off 0.3W
Phys. Dimension with Stand (WxHxD): 566x426x219 mm
Weight with stand: 3.26kg

What kind of surprised me here in a good way is that Philips, unlike most other manufacturers of FPR 3D displays lists the specifications for both 2D and 3D mode of the monitor. They list 12 degrees of vertical viewing angle (6 up and 6 down from the center) for when in 3D mode, something that most others kind of miss to mention in their specifications, and not everyone knows about the very narrow vertical viewing angle that is actually common for the passive 3D technology. And this technology limitation is more of a problem for the passive 3D monitors, because you watch them from closer distance, than for 3D HDTVs where you have larger screen that you watch from a distance. The other common drawback for passive 3D technology is the half vertical resolution you get when in stereoscopic 3D mode, though the technology also has its advantages over active 3D solutions as well. These are things like more affordable glasses, no flickering etc.


philips-236g3dh-bundled-3d-glasses


With the monitor you get two pairs of passive 3D glasses, one is traditional with full frame (the lenses are solid plastic, not from foil) and the other one is a clip on to use over prescription glasses. So not the cheapest possible solution for the 3D glasses, and the lenses and the frame are comfortably big as I’ve seen other manufacturers presenting a bit smaller and not so comfortable glasses. The good thing with passive 3D technology is that you can easily find a lot of alternatives for 3D glasses that will be compatible, from more affordable traditional solutions to specially made designer glasses, they just need to be compatible with the RealD technology that is also used in many 3D movie theaters.


philips-236g3dh-supported-3d-modes


As already mentioned, this monitor has two HDMI 1.4 inputs and supports Frame Packaged 3D input, but you should be aware that using this is not always the best choice, especially if you plan on using the 3D monitor for gaming. HDMI 1.4 frame packaging is limited to 720p 50/60Hz 3D (good for gaming) ор 1080p 24Hz 3D (good for movies), and while you also get support for Side by Side (both L-R and R-L) and Top/Bottom and Bottom-Top modes that you can manually activate from the monitor menu, these do come with additional reduction in resolution resulting in not so good quality on top of the already halved vertical resolution that you get with FPR 3D. One of the best things of the passive 3D monitors however is that regardless of what interface you are using you can directly feed them with Row Interleaved 3D data and have it displayed in stereo 3D, and this is the best choice for gaming as it helps in minimizing the input lag and gives you the best possible resolution and refresh rate you can get out of the monitor – 1080p at 60Hz in stereo 3D mode with half vertical resolution. The monitor comes with the TriDef 3D software as a solution for playing games in stereo 3D mode, though if a game (of application) has native stereoscopic 3D support and works with Row Interleaved output you can directly use that without the need of intermediate software.


philips-236g3dh-uncalibrated


Time to check the color performance of the Philips 236G3DHSB passive 3D monitor as well as to see how the measured default brightness and contrast levels measure up to the specifications announced by Philips. As expected from a TN LCD panel the color reproduction out of the box is nothing special, but it is still Ok for a TN panel, though we’ve seen models that perform worse. The maximum brightness level measured with the factory settings was 262 cd/m2 which is a bit over the officially announced 250, the black level is 0.24 cd/m2 bringing the contrast up to 1103:1, again over the 1000:1 typical from the specs.


philips-236g3dh-calibrated


With a color calibration performed trying to retain the maximum possible brightness level with best color reproduction quality we actually can achieve surprisingly good results. With maximum brightness level of 222 cd/m2 the display is able to provide really good color reproduction as with average of 0.5 Delta E it is really comparable to good higher-end panels in that aspect. The black level remains at 0.24 cd/m2, so the contrast has to suffer a slight reduction, but it still remains quite high at 920:1. So up until now we are seeing very good performance results, but lets us see how things will be in stereoscopic 3D mode.


philips-236g3dh-extreme-crosstalk


Starting with the extreme black and white crosstalk test photos to see how things look in close to worst case scenarios, though you’ll hardly get in similar extreme conditions when using the display normally in stereo 3D mode. The situation with the white is really good, the black is also quite good and these are extreme case scenarios with really high contrasting objects on completely white or black. Here the results are very similar to what you can get from pretty much any more recent passive 3D monitor.


philips-236g3dh-sailboats-test


The sailboats 3D video test shows great results, no visible crosstalk at all. Most 3D monitors show a bit at this test, so not having any here means very good performance. Most 3D monitors show a just bit if they are performing well, while 3D HDTVs usually don’t have crosstalk at all in this test.


philips-236g3dh-tru-top

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And finally some real-world tests using the game Tomb Raider Underworld in stereoscopic 3D mode, a good example to show that the Philips 236G3DHSB does indeed have just a little bit of crosstalk and performs very well in stereoscopic 3D mode. The monitor has a Smart Response mode available in the OSD menu that is intended to control the overdrive functionality of the monitor (to make the pixel response time faster, from 5ms to 2ms), but there is not that much of a difference visual in terms of actual responsiveness of the display, it does not visually influence the level of ghosting/crosstalk either. This feature probably could be beneficial for a 120Hz refresh rate monitor, but for a 60Hz model like this one it does not make a visual difference.

The conclusion about the Philips 236G3DHSB passive 3D monitor is that it offers all the features that you’d expect to get from an FPS 3D monitor, provides very good performance in stereoscopic 3D mode and comes at a decent price (you can find it for about 200 Euro in Europe or even a little less). It might not be the best passive 3D monitor out there, but it certainly shows good potential to be among the ones that provide really good results. Of course there are passive 3D displays with IPS LCD panels available, but that does not help much in stereo 3D mode and can be considered as an extra only for when using the monitor in 2D mode. So if you are looking for a 23-inch passive 3D monitor and are on tighter budget, you might want to check the Philips 236G (236G3DHSB) out as an option if it is available on your local market, as it seems that this particular model is not available everywhere.

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LG Has Announced an 84-inch 4K Ultra Definition 3D-capable HDTV

August 22nd, 2012 · 11 Comments · General 3D News


Today LG has officially announced what they call the world’s first 84-inch Ultra Definition (UD) 3D TV for the Korean market with the TV expected to start appearing in North America, Europe, Asia, and Latin America starting in September. What is interesting here is the fact that you get 4K resolution in 2D mode and more than Full HD in stereo 3D mode since the 3D TV set uses LG’s passive (FPR) 3D technology that essentially halves the vertical resolution in 3D mode. And the good news is that the 4K resolution (3840×2160) is actually fully supported by the HDMI 1.4 interface and thanks to the use of passive 3D technology you can also use the interface in 3D mode as well, though you’ll have to feed the TV set with Row Interleaved video data directly as HDMI 1.4 does not currently feature frame packaging support for more than 1080p resolution.

The 84-inch LG 84LM9600 Cinema 3D TV is definitely an interesting approach from LG as the company is clearly targeting to get a good market position among the 4K resolution TV sets even though they are still very far from becoming mainstream. And the good thing is that even the currently available technology allows them to support stereo 3D mode, though not in the full 4K resolution, but with more than enough pixels at 3840×1080 per eye for the 3D mode. 4K stereoscopic 3D support with active 3D TV sets at this time would be a problem due to the very high bandwidth requirements in order to push two frames at full 4K resolution, but with all the interest in 4K we are probably soon going to get a new revision of HDMI supporting frame packaged 3D at over Full HD resolution. The good thing from all this is that we are probably also going to have support for 1080p 60Hz frame packaged 3D mode sooner than later, so while 4K TV sets at every home is something still in the not so near future, we may all benefit from that even in the next generation of Full HD 3D-capable solutions.

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