More Distortion On 8k Than 5k Plus (MRTV)

Dear Pimax community,

in the last days I thoroughly tried to find all the differences between the 8k and 5k+ so you can make an educated decision.
I have found out that there is more distortion in the 8k as compared to the 5k if the devices run at full panel refresh rate.

See the second part of this video:

(Great thumbnail, right).

So the problem is: both headsets use exactly the same distortion profile. However, on the Pimax 5k+, this distortion profile is applied to 11 more frames every second. And that is why for fast head movements, you will see a difference as compared to the 8k.

Where things in VR perfectly stay in place on the 5k plus at fast movements, on the 8k they would move a bit with you. It is not a deal breaker, but it is noticeable.

So I felt it is important to let you know before you make your decision!

Sincerely, Sebastian


Reprojection? (20. etc. etc)

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@mixedrealityTV If the 8k ran at a lower FPS, but got better consistency in frames delivered, you probably would not notice the differences, or a wobble as much. 90hz and even 80hz areamazing, but only when you get that rate consistently rock solid.

For instance, I have the Gear VR innovator edition which is limited to 60hz. There is a fast motion game that requires rapid head movement as a matter of gameplay, called smash hit. As long as it stays locked at 60hz it doesn’t induce motion sickness, (even though things are whipping by you rapidly. As long as low persistence is active, and frame rate consistent, it works well.

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Surely they will change in an update, right?


Sounds like a software issue to be addressed later. Can’t possibly be a deal breaker

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I find it interesting that you detected this distortion when doing the “movie” testing rather than during gameplay.

Why are you moving your head so fast while watching movies? What were you watching at the time?


Yep, the problem is that there is still distortion in general. If there was no distortion at all, then you would not see the difference between the 80hz and 91hz.

But since there IS still distortion, this little distorion becomes more apparent when the distortion profile is applied 11 frames less often on the Pimax 8k as compared to the Pimax 5kplus.

You don*t really see the difference on demanding games, when the framerates are both below their panel refresh rate. So yes, for those games that do 80 and 91 fps…you will see that difference.

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Haha…no, I didn’t see that in movie watching. :slight_smile:


Nope, that can’t be fixed in software. You could fix it in software by makeing the 5kplus equally bad as the 8k by forcing only 80hz, but that would be stupid.


Its because the movies are a fixed frame of reference. For example, if you are in bigscreen, Oculus video, or another app in a theater environment, you notice distortion even on OLED during a rapid head movement.


but why not give the 8K a 8K profile and a 5K+ a 5K profile?


The opics are the same, they should have the same lens distortion profile. But again, the main difference is the 80 vs. 91 hz. If the Pimax 8k could also do 91 hz, we would not see the problem.

are you using normal FOV or High FOV mode when seeing the distortion?

Would the different screens not affect the distortion profile? I believe it’s been mentioned that the 5k+ new screen might be a little smaller than the 8k’s screen?

Could the perceived lack of visual quality be partially due to this distortion?

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but i mean, give the 8K it’s own 80hz profile, and the 5k this 91 hz profile…


Well, yes but…ehh no, wobbling cant come from frame rate, its more like shadowing what you are talking about; insuffisant ms response from lcd pixel issue.
I mean with 3 fps at 3htz you would have 3 images, left front and right but only one at time, with shadowing, pixel didnt change color fast enough so when moving right and left there is the…shadowing effect you seems to describe, which is something the 4k had seriously with hi contrasts.
Pixels leaving a trace behind them…a shadow, pixel persistance it is.

And distortion is for example when you have a square on your left that doesnt looks square because of the image distortion that have to be adjusted when in front of you…just like when watching 360° on a flat screen, its distorted.

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You would see the problem more if the 8K ran at 90hz, because the thing cant hit that rate, except on an insane video card. I know it sounds counter intuitive, and even dumb, but a lower FPS that hits the Motion to photon window every time consistently is better than a higher hz that misses its target and drops frames.



Can you confirm it’s not the curves of the booty you are seeing?


Damn, I should have done a separate video! :slight_smile:


Can you tell us if you are using the updated PiTool please?