It looks like the San Francisco demos should be over (assuming they are only doing them today 9-6). Did anyone get a chance to have a look? Most importantly, did you experience any warping, was the screen bright enough, and how does it compare to the rift/vive?
I know a lot of people are eager to here reports from anyone who’s experienced it.
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I went into the demo thinking that the stretching was going to be really bad. However, I didn’t really notice any stretching at all. I believe they have fixed this, at least for fruit ninja. There was some non-uniform warping near the edge of the lense, by non-uniform I mean the warping was kind of in a zig zag pattern from the top of the screen to the bottom. However, when looking straight its way out in the periphery, so most of the time I didn’t notice it.
Overall, it was a good experience. That FOV and resolution were amazing, it might be hard to go back to the Vive after seeing that. I didn’t notice any screen door effect, and could only make out the pixels when specifically looking for them.
I think my eyes were very close to the IPD sweet spot, because when placed on my head just right the image was very clear.
My biggest problem with it was the brightness & contrast, the screen seemed a little dim, but others said they thought the brightness was fine. I think given a longer demo my eyes might adjust. I also noticed some very subtle stutterers like a framerate issue. I asked about the FPS we were getting in the game, Robin said 80-90fps. So maybe it was due to dropping below 90 fps.
We also got to try the 5k OLED version, with a different demo. Not sure exactly what demo this was but you were in a dark room with brightly colored lines making up the scene. Since most of the image was black it was difficult to judge the resolution, SDE, stretching, etc. I believe this demo was more to show off the hand tracking unit, which worked very well.
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First off, the negatives.
Controllers really aren’t great. Not a fan of the glossy touchpad or trigger (it also felt like it wasn’t analog), and the grip button isn’t great either. We were only using one for Fruit Ninja, and it was wired to the PC (over USB-C I think). They said they didn’t have the dongles with them (I assume they meant the Watchman Dongle that’s used for the Vive Trackers/Controllers/Steam Controller), but the final headset will have integrated dongles (like the Vive). The cord came out several times, and while I was playing it lost tracking once and wouldn’t work again until everything was restarted.
The lenses had visible distortion around the bottom and edges. I didn’t notice distortion caused by the non-planar panels, but that may have been because I was focusing more on the lens distortion.
In Fruit Ninja I could tell there was a little stuttering with the MSI GTX 1080 laptop.
Lastly, the tether was very short. This needs to be much longer.
Positives
The FOV was great. We could still see a bit of blackness at the very edges, but the binocular effect is gone. I haven’t been using my Vive as much recently, so I wasn’t as blown away as some of the others, but I put on my Vive at home afterwards and it felt much lower.
Clarity/pixel density on the 8K felt similar to the HoloLens. A few of us tried BigScreen on it and text was sharp.
The hand tracking module was very good. Hand tracking FOV was much wider than the current Leap Motion on my Vive, and my hands were tracked perfectly.
Other Thoughts
We didn’t get as much time with the 5K. The only thing we tried on it was the Leap Motion Mirrors demo.
Robin said the lenses will be redesigned and the new ones will have better distortion correction calibration.
They said the controllers will be redesigned with capsense to be more like the Knuckles. They asked for feedback at the end, and I suggested first focusing on making the buttons better first.
The deluxe bundles will have SteamVR Tracking 2.0 base stations.
Both use fresnel lenses. Godrays/glare is still there, but a lot less noticeable than on the Vive or Rift.
The 8K headset was upscaling a 4K input.
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That’s awesome to hear. Do you fell like the small edge distortion was in the image or due to the lens? Also how does it compare to the vive and rift?
Awesome so it definitely gave you the feeling of being in a 3d world? There was no distortion or weird effects when you turned your head? And big screen had the screens with no warping or anything?
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I have to say this looks very, very hopeful 
Me excited! 
Did you get any more detail on that? It would certainly be possible to upscale 2x4K from one 4K, using a variety of patterns including stippled, line interleaved, column interleaved, side by side or top and bottom. It would require more bitrate than the 2560x1440 mode they’ve confirmed previously, moving up from a 2.25x pixel count upscaling to just 2x. Brain warp would work better with one of the last two depending on image orientation. I wish they’d just publish a list of modes they’ve got working and are still trying.
As for the edge distortion, simple curve fitting models like the polynomial approximation typically used do break down at the periphery. This could be indicative of a somewhat incomplete parameterisation; it could be they’d get a better model by calibrating a larger lens, placing the edges of the distortion model outside the edges actually seen. Another option is to actually reduce the degree of the polynomial.
Did they give any more info on improvements to the next prototype ready this month?
So far you have said the lenses will be re designed to accommodate for distortions. Did they say anything about improvements to the displays themselves?
Thanks in advance
Was the brightness bad?
yes, all good news these reports make me very hopeful pimax will ship a good product.
excellent.
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looks very promising , at least one game will be playable - Fruit Ninja ! 
Edit , just found Eve Valkyrie (?) demo with pimax 8k : 8K HMD Test (Pimax) - YouTube
I’m a little concerned about these framerate issues. Several people now have mentioned that the framerate didn’t seem perfectly smooth, but they’re running fruit ninja on a 1080, for crying out loud. There should be no issues with framerate whatsoever from a GPU power perspective. Something else must be going on in the processing or “brainwarp” software. Pimax, is this being addressed?
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I don’t know if you remember how screwed oculus became when they demo’d doom at a convention. So they may have gotten permission to USE fruit ninja.
So we now have reported as current downsides:
- Stretching, which probably was caused by wrong IPD, since others report no stretching
- IPD adjustment process itself, it seems it’s not working well. Might be difficult to fix since panels don’t move.
- Brightness seems too low for some, others say it’s fine. Obviously it’s not bright enough for everybody.
- Warping/distortion around the edges, I think reported by everybody
- Stuttering even in an extremely simple game like Fruit Ninja, might be a driver/brainwarp problem
- Native resolution not available, planned for mid 2018.
- Controllers are quite bad and currently also are not wireless. They’re working on better controllers.
Unfortunately it’s starting to look like this is going down the same path as the 4k: half baked product during release and then over the course of years improvements.
This showed up in the /r/vive reddit from user critters:
First a little bit of background info from me to give my “review” some context. I owned the DK1, DK2 and currently run the Oculus (with touch) in my office for seated experiences (mostly driving & virtual desktop / big screen) and the Vive in my 8’x6’ living room for room scale. I’ve upgraded my Vive with the audio strap and new slimmer cable
I have backed the kickstarter, ordering the 8k headset, and plan to use my vive controllers and base stations. I feel it’s important to mention this due to a cognitive bias we humans have called “Post-purchase rationalization”. It is possible that my backing could have influenced my experience, but I will do my best to be fair to both the Pimax headsets as well as the Oculus and Vive I currently own
The Setup
The Pimax demo took place in an office in San Francisco and consisted of two of their base stations, one controller, the Pimax 5k with their hands on module (think leap motion), and the Pimax 8k headset without the hand module. They were both running via a laptop with a GTX1080, no details on CPU or RAM but given the GPU I imagine they are “decent”. About 15 people attended the 2 hour demo
Pimax are using Valve’s tech, which means you can use existing lighthouse and controllers with the Pimax headset. You could opt to get their lighthouses and controllers bundled with it if you currently don’t own any
The term “8K”
In some past posts about this headset people have gotten their knickers in a twist when it comes to the naming of the 8K. The “8k” refers to the horizontal resolution of the combined displays which are 2*3840x2160 (7680x2160 combined). An 8K TV or Monitor would most typically be 7680×4320, so the “8” in this case refers to the horizontal resolution matching that of a 8k 16:9 display. Personally I think this is the correct way to report VR resolutions given the unique aspect ratio. For comparison this would make the Oculus and the Vive “2k” headsets
Both the 5k and 8k are fed a 4k (wide) signal from the laptop which they upscale to their respective displays. This was via HDMI but the final version will use Displayport. This lower input resolution combined with fast switching between left and right eye rendering is how they can run an “8K” headset with a min spec of a GTX980/1070.
They do have a version of the headset in development called the “8K X” that (via two displayport connections) accepts the display’s native resolution of 7680x2160 with no scaling… but that is shipping later and would require SLI 1080ti (or next gen) to run!
The 5k with hand tracking
First up was the Pimax 5k with their hand tracking module installed under the headset and Magic Mirror “game” running on the laptop (note the video I linked is just to show the game, it was not captured from the event). The module attaches to the underside of the headset via its USB-C port and 2 screws (no cables). It’s very slim and blends in well with the headset design. I was told he FOV of the Pimax hand sensor is 180° wide, compared to 150° on the leap. I had no data on vertical FOV
The 5k features an OLED screen which is why they probably picked a demo with a lot of black in it, and the blacks were VERY black. It was hard to make out sharpness given the motion blur on the particles and the trippy nature of the demo but the hand tracking was amazing. I’ve not used the leap myself, but one guy who attended the demo who has said it was “quite a bit better”
There was never any 100% white on 100% black in the Mirror demo, but the particles were quite bright and I can report that I noticed no god rays or halo/bloom, something I notice instantly in both the Vive and Oculus in any high contrast scenes
The 8k
Switching to the 8k headset they fired up fruit ninja and handed us their prototype controller. The 8k uses the same lenses and is otherwise identical in appearance to the 5k but instead of a 5K OLED it features their custom 8K LED screens. As fruit ninja is quite a bright and colorful game I was able to get a better look at both the 200°FOV of the headset as well as the performance of the screen. First up, I’m happy to report they have solved the edge stretching that the Tested guys commented on in their review. There was still some lens distortion around the edges, but I was told that will be fixed with the next iteration of the lens and a tweak to the software prior to shipping. After a bit of play I started to ignore the distortion and focused on the resolution
I could not see ANY screen door, chromatic aberration, or sub pixels while looking around the Fruit Ninja space and holding the sword close to my face. I could look far to the left and right using my eyes and even at the extreme of my eye-turning ability the image was pin sharp, which was unexpected. Like the 5k I noticed no rays or bloom but it was a bright scene so I wasn’t expecting to see much of that anyway
As the fruit flew and my sword chopped I noticed no ghosting or smearing of the motion
After the demos were over I asked if we could jump into Big Screen to check out a web page. For the first time I could read the clock in the corner of the windows taskbar and the text in the browser URL bar clearly with Big Screen’s default screen size. On Oculus I need to scale it up some or lean in to easily read text that small. I don’t think it’s a viable monitor replacement yet, but I think it’s totally usable for some light web browsing, IMing, and reading and responding to emails. Though we didn’t get to test any, I imagine movies look amazing in it and look forward to kicking back in a Big Screen movie theater
The controller
I don’t feel it’s fair to comment on their controller for a few reasons: 1) The controller we used was a prototype, it was even held together in part by some tape 2) They plan to ship with a new design that features some of the tech from the upcoming Valve ‘Knuckles’ controllers, so any review would be invalid 3) Fruit ninja didn’t use any buttons so I pressed nothing. I can say the tracking was as good as the Vive, which is to be expected given it uses the same tech and looks the same as the Vive controllers
Conclusion / TL;DR
PROS
The screen/lens combo is so far ahead of the current Oculus and Vive it’s ridiculous. No screen door, little to no rays or ghosting. Deep blacks on the 5k OLED, no chromatic aberration or “ripples” from a fresnel lens, no visible sub pixels, no noticeable smearing
Despite looking bulky, the headset is light, lighter than the Vive apparently, and didn’t slosh around as my head turned quickly
The 200° FOV is something you won’t be able to go back from, using my Oculus now feels like i’m viewing the world through a scuba mask!
The hand tracking module works well and integrates well with the headset
Is launching with optional modules including hand tracking, prescription inserts, fans for face cooling, and replacement pads… more modules including eye tracking and inside-out tracking planned
CONS
Some (though not I) people who attended the demo said the display on the 8k seemed a little dim. Given they are alternating left and right and inserting black frames to remove ghosting (I assume) this makes sense, but then the demos were short and the room was bright, I think after 5 minutes your eyes would adjust. I personally found the brightness perfectly acceptable and only bring it up because others mentioned it
v2 of their lens still has some distortion, apparently will be fixed in v3, but only have their word for that
I’m looking forward to receiving my headset and swapping out the headset on my Vive setup, happy to answer any questions you have. You can view the FAQ and more detail about the 5K, 8K and 8K-X on their Kickstarter Page
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Thanks. One positive thing that everybody mentioned is the lack of ghosting. Pimax seems to have solved that, which is very positive, since it’s still a huge downside of the 4k.
Other than that, this stands out to me:
This is not my review. I just re-posted it.
I got that, thanks for posting, well written review.
It appears to be in r/virtualreality, not r/vive, but here’s the link:
I got to demo the Pimax 5k and 8k headsets, here's my initial impressions : virtualreality
Great review ! Starting to get excited again, it looks like Having a big HEAD will be An advantage to someone using the 8k lol
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