The Spanish Inquisition Team - The truth, the whole truth and nothing but the truth (by Neoskynet)

Pimax 8K Series
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Don’t trust the pictures or the videos because they don’t tell the truth.

I’m Neoskynet, from the testers group “The Spanish Inquisition Team” that participated in the development of Pimax 8K and we gave our sincere opinion about the improvements that could be applied before sending the devices to the backers of Kickstarter.

Anyone who has tried to take a photo or video to a TV, projector screen or VR headset will find that what appears in the images and what their eyes see is very different in colour, sharpness, perception of blacks and whites, field of vision (FOV), chromatic aberrations, peripheral distortions, etc, etc, etc. The photos and videos look very good on Youtube to get subscribers eager for information, but the reality is that they are totally useless to know the truth.

Tests with a single device (TV, projector or VR) are also not valid because human visual memory is very deficient and adaptive. It doesn’t remember the changes after a while and in a few minutes a bad quality image will look normal or even good.

The most reliable test I know so far is to make on-site comparisons (hot swaps) with two devices (TV, projector or VR) with the same image, change the image of the devices in a second, many times, and one or several people give their sincere opinion about what they are seeing.

These opinions will be much more real and closer to reality, because that person will be able to move their eyes to focus different parts of the image, turn their head to notice the peripheral distortions generated by the movement, focus near and far to check the sharpness and Screen Door Effect (SDE), look at dark areas to see if there are good blacks and shades of gray, see the balance and naturalness of the colors, measure the field of vision (FOV) and many other things that are impossible to do with a video camera or photo camera.

We will start with a comparison between HP Reverb and Valve Index, and I hope to make more comparisons between Pimax 5K+, 8K and the new 8K+ and 8KX versus other VR devices following the same methodology.

It is my hope that these comparisons will be valuable for everyone and that Pimax will decide to send us 8K+ and 8KX devices to make more honest and valuable comparison videos.

The video is in Spanish and you can activate the translation of subtitles to English.

Cheers,
Neo

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Interesting! (Still listening)
For people who understand at least a little English it might be advisable to use English subtitles. At least Spanish->German is almost completely incomprehensible, even with a lot of fantasy :stuck_out_tongue:

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Awesome Neoskynet! Very true. :beers::sunglasses::vulcan_salute::sparkles:

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I’ll try to teach Pacotaco to speak German, but it could take several years. In addition, Pacotaco’s mixture of German and Gaditano (a Spanish slang) could be deadly.

Cheers,
Neo

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Long time no see @Neoskynet NOBODY EXPECTS THE SPANISH INQUISITION!

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The Spanish Inquisition Team appears when nobody expects it and puts the whole truth on the table…

… even if it means torturing a few liars, blasphemers and infidels.

And yes, the next one could be you.

Cheers,
Neo

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Single pictures don’t deliver anything useful, I agree with you, but comparative pictures under the same conditions already give a clue. But they only give you a clue if you have one of the headsets that were compared. Therefore, as an 8k owner, I am very grateful for swevivers macroshots, which also contain an 8k.

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Thanks a lot for being honest and helpful.

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I share your thoughts - @kellerbach.

it’s nice to have more insights From neoskynet and others ( as always ) and never good to trust a single source ( no matter what single source). All are to some degree subjective descriptions- sum it all up and it gets a bit closer to truth.
For me the pictures from sweviver are just as valuable as your experience, neoskynet.

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The 8K-X is without a doubt a monster, BUT, so is the Reverb.

So the real question would be:

  • Does the increased resolution + FOV of the 8K-X makes up for the difference in price between the two ?

Which brings us to some questions:

  • Does the screenshots are always at FOV LARGE ?
  • Can the actual panel usage be disclosured ?
  • Can we get some more pictures (we really don’t need macro shots) of text in Virtual Desktop ? (this way we are always at the same distance from the screen)

I am VERY tempted to buy the 8K-X (after the site being fixed, sorry but i will not pay $500 in taxes) but we need more evidence of it’s capabilities.

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@risa2000 hmdq tool reveals info like panel utilization. I believe with HAM values.

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Actually it is not a panel utilization, but render target rectangle utilization (which is partially masked by the HAM). For the panel itself there is no way to figure it out without either looking at the panel, or ripping out some images from the pipeline right before they are sent to the headset.

For what I remember from my past tests, in Normal FOV, the image takes 2/3 of the horizontal resolution of the panel (on P5k+).

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Exactly, so if the 8K-X don’t have a higher horizontal panel utilization it could, COULD, be worse than the Reverb because of the large FOV.

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Okay my bad thanks for clarification. Hopefully the team will see your example. :beers::wink::vulcan_salute::sparkles:

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If we assume that 8K+ and 8K-X has the same lenses and the same panel size as 5k+, we can estimate the pixel utilization by using 5k+ model I mentioned above, which is: for Normal FOV, image takes 2/3 of horizontal res.

Now:

Pimax 8k+/8k-X estimate
single eye horizontal FOV in Normal mode for 5k+ is 113.54° (HMD Geometry Database | Collected geometry data from some commercially available VR headsets.), assuming the same FOV on 8k+/x, horizontal panel res is 3840, but roughly only 2/3 is used:

3840 * (2/3) / 113.54 = 22.54 average PPD

HP Reverb
single eye horizontal FOV is 91.37°, panel res is 2160 (and assuming the image uses the full horizontal res):

2160 / 91.37 = 23.64 average PPD

So it is almost the same. I would not take the results absolutely, since there is some estimation involved on 8K+/X, PPD is not same over the whole FOV and the optics is different (HP Reverb seems to have smaller “sharp” spot than 5k+/8k according to the feedback).

But on pure pixel utilization 8k+/X and Reverb should be basically the same, because the pixel utilization on 8K+/X should not change with different FOV (Small/Normal/Large) because it is only defined by the optics and not by the rendered FOV configuration.

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After Pimax revealed the 120hz mode on the 5K+ it got me thinking if they could do some kind of pixel shifting super resolution like projectors on the 8K-X on small FOV.

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Awesome insight Risa2000 !

This is why i am hoping for much bigger panel utilization on the 8K-X.

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I believe that if they use the same optics, they cannot really do much about it. There is a trade-off of being able to see the large FOV (in Large FOV mode) and then having the panel to be used only partially in the other modes. Plus Pimax also needs some margin for an IPD adjustment, which also decreases the overall utilization slightly.

If they designed different lenses which would use the full horizontal resolution (except the required IPD margin) for smaller FOV (e.g. something like today’s Normal), this could improve the PPD significantly, but this will require different lenses and then you would lose the Large FOV feature.

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@kellerbach and @MReis, I agree with you. More information is always better. But having partial information is worse.

Don’t give too much importance to macro photos and image and video comparisons through lenses because they can give a wrong view of reality and there are so many more important things to keep in mind in the VR.

About @SweViver, I like his videos, especially two:

  • The first video in which he courageously dared to take out the 5K+ and 8K lenses and show the black zones and the low use of the screens, since a few weeks before I had taken out the lenses myself and explained it to him in a videoconference between @SweViver, @Cdaked and myself, by Skype.
  • The second video in which @SweViver explained the great sharpness due to the high utilization of the XTAL screens and the low sharpness of 5K+ and 8K due to the low utilization of the screens.

However, the last video between the HP Reverb and the 8KX are very badly made, blurring the HP Reverb. I think @SweViver can do this much better.

I would like @SweViver to make a video taking out the lenses of the 8KX to check the black areas and the real use of the screen. And @SweViver compared the lenses of the 8KX with the 5K+ and 8K to see if they are the same.

The HP Reverbs I have are only good for the almost 100% use of their screens and the consequent enormous and extraordinary sharpness. And indeed, the Reverb lenses could be much better.

My recommendations for Pimax 8KX would be:

  1. Develop a system of three interchangeable lenses to choose a physical FOV of 120, 140 and 160 horizontal degrees with each of the lenses (different magnifications) and a lens selection option in Pitool. The 120 degree lens would dramatically increase the sharpness and at the same time reduce or even eliminate the current distortion problems (although the form factor would cut the vertical FOV in black when reaching the limit of the screens). The great advantage is that future and better new lenses could be used. Although I still think that the search for a huge and impossible great 160 degrees horizontal FOV is impossible with the current lens technology and is also pure marketing and the origin of all the problems of lack of sharpness.

  2. That the screens move together with the lenses. Now the screens are smaller and can do it. This would avoid IPD adjustment problems and would also allow you to take advantage of the 10-20% reserved in black.

  3. Improve the mapping of distortions, deformations, the world moves (yes, it still moves by lateral deformations in the form of image stretching). It still has too many problems of this type, and is the worst enemy of VR because it tides. It also gives the feeling of a bad and unfinished Chinese product. If you don’t believe me, compare some old HTC Vive 1 and 5K+/8K exchanging viewfinders (hot swap) and playing in fragments of 1 to 5 minutes and you will notice the big difference in favor of HTC Vive 1.

After so long waiting, I think it is NOT valid to sell Pimax 8KX with the same case, the same lenses and the same waste of screen and sharpness. For $1299 (only the VR headset with no base stations or controls) we want a lot more. Pimax 8KX could lead the market for high-end VR viewfinders.

And very good work @risa2000. You’re right.

The anyway, as always, the Pimax team will ignore us. Although my hopes are on @SweViver, now that he works for Pimax, as he knows very well everything I’m explaining and I’m sure he agrees on many things.

Cheers,
Neo

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I agree,
but also some points have been at least vocally adressed --> the housing is supposed to be overworked and has / will have a different finish for the 8K X, I think it was stated that the panel utilisation is better since its size is a bit smaller and better fitting to the optics.
Ok lenses would have been awsome -, but I have no real clue on this, so just dreaming/guessing that I would really love to see a cooperation with some one like Zeiss that makes very good optics and might be “more easily” up to doing a better lense then almost all VR Companys have, then on the other hand (not saying that is good) even the large boys often throw the same kind of lenses in there HMD and they are still much smaller.

I like my 5K+ and really love the experience in large FOV especially with the 120Hz Mode (ok GPU is near meltdown, but thats not their fault) looking at the current market I dont see much competition for my usage case, thats why I like both the 5k+ and 8k X!
I think PiMax is doing a good job at pushing VR Forward - but need to learn to Communicate (x Infinity) and ramp up the quality. So looking at my wet VR dreams - there is still head room in the hardware and software, looking at the current market - its a damn good job - not perfect, but damn good for a small player!
That you all are disecting the Hardware is good, it clears up the real situation, for me personally also the Makros do that - knowing its just a small part of the overall.

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