Some thoughts about resolution, FOV, and comfort after comparing 5K+ and Index



Ha, believe me, I’ve tried them all. I also tried every other trick out there like moving the HMD up/down/away/tilted. I see 3 possible reasons why some, like you, don’t experience distortion and why others like me do:

  1. We have different hardware. Pimax seems to have done several revisions, this might be a factor
  2. We have different physiological features. I could imagine that the specific tilted angle of the panels for example works better for some faces than for others. Also I imagine properties (like size) of the eye/iris itself could have impact.
  3. We experience things differently. Like some seem to notice a big difference in frequency 90/120 hz on the Index and some don’t, maybe some are more prone to perceiving distortions than others.

I tend to think it’s mostly point 3. In a scenario where the iris position changes so much (ultra wide FoV like the Pimax) I don’t really see how it’s possible to have 0 distortion with a fixed distortion profile. See also my comment here, way back before they even created the 5k/8k: 110 degrees Fov stretched to 200 degrees? EDIT: All the games render in a native wide FOV through the engine After that, StarVR revealed that they solved distortion issues exactly like that: a dynamic distortion profile based on the position of the iris (so each frame the eye tracker checks the iris position and applies a distortion profile for that frame, for that iris position). So that makes me think my theory there was correct.


i have to agree with you here, the other day I realized that for me the pinax 5k+ the distortions dont matter much for games where you are stationary. Exqmple driving or flight games, even gamea like beat saber and superhot are ok (you dont realy walk around in them and even if you did the backgrounds are all black or all white so youbwouldnt notice distortion as much)

However the second i tried Arizona Sunshine I was in awe at the beautiful FOV , then i took a step and I felt like I had vertigo, it was the most unpleasant thing ive experienced in VR in 3 years.

At this stage ive bought a used OG vive so i can use the pimax, and I have knuckles on the way, (cant stand vive wands) so im 2/3 of the way to Index-ville.

I have been forced to play stand-up-and-walk-around games on Small fov for now.

Index may be better for general usage, but pimax will probably win for sims.


Distance from lenses, tilt and vertical placement are equally important from my experience. Sweetspot where geometry on Pimax looks correct seems to be very small and easy to miss.
Right now, after using and tweaking headset for months i can say that geometry (sense of correct 3D depth and scale) in SkyrimVR is very similar to Vive with thin facepad, at least in the ‘main’ central viewing area.


As soon as I put on another hmd after pimax, I get the sigh of relief…’aah that’s better’. Even though my pimax is a better experience now than several months ago when I packed it away.
Specs on paper don’t mean much in vr. Trying on another hmd still demonstrates to me how far off pimax are. I’ll be packing it away again until controllers come…so a long time.


Give Magaton Rainfall.


I have exact the same opinion now i have an valve index and my pimax 5k…
this is what you said:

Well it is only a downgrade in terms of:

Better in the index are:
•colours & contrast
•SDE/pixel pattern visibility (slightly only though)
•Geometry/distortion/feeling of depth/immersion
•audio (beats any headphone i’ve tried)
•Build quality
•software/ease of use
•GPU usage
•Lens sharpness over a much larger area
•refresh rate

For me:
I use the index at the moment more as my pimax 5k


you are right, but if i traded my pimax for an index, then I found out that AirCar was released Id always have that nagging question

“what would this have looked like with that Large FOV”

Pimax excels at certain games, especially those where you are in a cockpit.

Index will never compare to that. Because for certain games all of the items you listed are weighted differently.

For cockpit games FOV is king regardless of distortion.

For stand-up-and-walk around games like Arizona Sunshine etc… Then FOV is of less importance than the other things that Index is better at.

Only way to win is to have both. Too bad switching between the two seems to require pairing the controllers everytime.


yes I agree once you reach 130 i think your FOV in your forward looking direction becomes unrestricted. You have no peripheral vision but what you see in front of you ,I can only describe it as “eye-opening”

but that is not to say going larger isnt important. 130-150 is more significant depending on the genre of game.

There are some exceptions for example superhot really benefits from being able to detect red dudes sneaking up beside you


I really believed I didn’t say anything contrary to what you are saying there (…yet now I’ve had to clarify this twice, so I guess I’m just bad at expressing myself); Not that 130-150 isn’t important - not by any means whatsoever, hell no; Only that I “feel” they are not AS important as the subsequent 170-190 (and beyond).

Not so much for the gameplay-situational spatial awareness, which as you say depends on where each game places incoming gameplay-relevant information, but for the “immersive” spatial awareness that roots you in the virtual world – The one that gives you a perpendicular-to-straight-ahead optical flow in your periphery, from your own motion, and which lets you (…by direct senory input, not internal mental mapping) “sense” the presence and location of a doorframe, even after you have just walked through it. :7

I would also value an unrestricted (…by the headset - one’s real world nose is a separate thing, which we have a bit left to to until we get to) stereo overlap higher than I would those particular “ante-peripheral” sections of FOV. :7


I don’t think we are disagreeing with you, we are just “thinking together with you”, adding to what you said. Since one of the core topics of the thread is if 1/3 less FOV is “good enough” looking at the question about diminishing returns from different angles is important.

I don’t think many people would completely disagree with that. The discussion here is not about somebody preferring a headset they feel they like more, it is about understanding the specs right. Things like: the FOV of the Index is the same as the FOV of the Vive with a thin cushion; the FOV of the Index is not “almost the same” as the 5k, but 1/3 less; the distortions are usually a question of setup and not an unavoidable problem.
I have always believed that choosing a headset is a question of personal preferences and priorities, but it is important to get the facts straight first before using them as an argument on a public forum.

This is a very good way to say everything important in a condensed way.
My personal experience is exactly the same - as I said above after adding DAS and the thicker Vive cushion dealing with the distortions is a question of IPD. And I agree that those 3 are equally important.

Hmm… It is one thing to not notice the frequency, another to not be able to tell apart a straight line from a curved one and morphing geometry. So your theory is basically that some people (like me) are too blind/stupid to see the problem.

I prefer to look at it this way: some people manage to get rid of distortions via setup changes (DAS+thick cushion+IPD), other can not. So the question is what is different between the two groups and the answer to this will help make it work for everybody.
There is a discussion here about people with asymmetrical IPDs, I would guess this is one reason why some people can never get a good result. And there are probably others.
I followed the link you posted and there I saw Pimax replying directly to you that they have been working on this for 2 years and have solved the problem you describe. Maybe what you describe is the reason why a thicker cushion helps and then the question becomes how thick is thick enough for different head shapes and sizes.

My personal issue with the thick padding solution is that it makes the effects of the incomplete stereo overlap more visible - the black plastic on the sides becomes more apparent. I made an experiment and with a thin enough padding the stereo overlap feels completely natural - there are no visible artifacts where it ends and it is positioned almost where the nose is so the brain doesn’t see anything unusual. But the distortions at that position are huge.


As soon as I put another hmd after pimax, I get claustrophobia…

do what you want, but in what way should the controllers change your problems with the pimax HMD?


I have perfectly symmetrical eyes. If one would have asymmetrical IPD’s they could just move the HMD left/right a bit over their nose, unless of course the IPD’s are so asymmetrical that they would have different angles (the type of person of whom you think “Is he talking to me or the guy next to me”), but I highly doubt anyone here falls into that category. Either way, like said, it surely doesn’t explain my case. But even more importantly, if it was due to such physiological differences, then those people would have distortions on ALL headsets out there. And the fact of the matter is that everybody reports they’re fine with other HMD’s and that it’s only the pimax headset that has those huge distortions. I do see them very slightly on the samsung odyssey+ too, I see none at all on the Vive Pro or Index. Valve explicitly said on their blog post that the wider the FoV, the harder it is to make it distortion free and that they didn’t want to deliver a headset with distortions:

Geometric Stability: As FOV increases, it becomes harder and harder to accommodate distortion and keep the image geometrically stable. Instability comes from many factors, but is most clearly manifested as a wobbliness in the world, where things that should appear solid instead undulate like gelatin as you move your head. We believe that providing geometric stability is a critical aspect to long term comfort and sustained growth of VR usage

And by the way, another reason that makes the Pimax VR world so wobbly/unstable (apart from the geo distortion) is that there’s a huge latency on the 5k+/8k, which has been documented very well here on these forums, even with a video demonstrating that


Did I do something wrong ?^^


Personally I’m not interested in anyone’s opinion that doesn’t own or at least have tried both headsets.

You cannot sit there mashing your keyboard if you haven’t actually used the other part of the argument.

I have friends in sim racing that bought the Pimax after I received mine. They loved it. They also bought the Index when it came out, as it was available in their location. Like me, they wanted the best sim racing VR experience and owed it to themselves to try it even after buying a 5K+. All of them have put the Pimax aside and are using the Index pretty much full time with better results.

I have one of them sending one my way as a huge favour. I too will be able to compare the both of them side by side. Having used (and absolutely fluffed around with) the Pimax for nearly 6 months, I think I will know straight away which one I will be keeping.

Another note, I too agree that the 130 ish FOV range is the ‘gateway’ to the most unrestricted forward viewing visual experience. Higher may be better, but not at the cost of image, for me. Using small gives a bigger super sample budget which is just as important in sim racing, as is frame rate.

Also, I cannot accept the fact that someone can refer to the Large FOV of the Pimax as its greatest feature, yet the same person calls the higher refresh rate of the Index ‘unusable’. Correct me if I am wrong on my math here:

Small > Large FOV = +50% increase in pixels rendered for same supersampled image quality
90hz > 120hz = +30% increase in rendering cost

Unusable ???


There is a difference between hard and impossible… You seem to think that it is impossible at the moment (as you believe only eye tracking can help) so nobody should try.
Yes, the big players did decide to stay in the safe zone and it is up to the smaller player to innovate and push things forward. And it is working - for some, and not quite working - for others. But the thing to do is to find out how to progress further and not to give up.
Yes,we know it is hard - that’s how progress happens - by overcoming hard problems.

If one would have asymmetrical IPD’s they could just move the HMD left/right a bit over their nose

Which of course would be unsustainable even for testing.


Hell no. Lol. No you demonstrated an endurance race using a pimax headset demonstrating that some do not experience strain wearing a pimax for extended periods of time.

Which is awesome but there are some whom are not as fortunate & experience it after short sessions.


One also has to consider that at least for the 8K, there is relatively little Geometric Distortion on Large FOV. There is of course less image clarity on the edges of the FOV but that for me does not detract from the usefulness of the Larger FOV be it 150 or 170.

130 FOV is by comparison quite restrictive and with my testing, using FFR - there is no benefit of using the smaller FOV performance wise. With the larger FOV I can know placement of my VR world and objects and can detect threats in such. If I notice a threat in my periphery, I can then move my vision to center it on the display and Identify it properly. This is a big deal for me in simulated combat with multiple adversaries and my moving in 3 Axis.

At high render target resolutions, there is little between FFR on and off visually but quite a performance boost in FPS. It is a quite something for Wide FOV headsets even if it is only fixed at this point in time.

Anyway, each to their own and if Pimax is not for you - there is the door and enjoy your Index. This is the Pimax forum and there is no need to pollute it with repeated negative comments. Once should be enough and know that behind the scenes things are being worked on to hopefully improve the experience. It is good there is competition but aside from HP, I don’t see anything really pushing the tech along as an alternative to Pimax. The rest is too little too late and every headset design has its issues.

This comment is more directed at Anton


The refresh rate is subjective as much as FoV is. Some have greater sensitivity to one. This also comes down to preferences.

In truth for overal Sim experience if HP hadn’t fumbled so badly it likely would still have a crown for simmers.


He never said that. Even pumax said they were considering using Eye tracking for dynamic distortion correction prior to StarVR revealing they were indeed using it. It does suggest that eye tracking should be part of the standard package for a better xp for a wider audience.

As for your presumption of being blind or stupid on geometric distortion is non sense. As folks wearing glasses don’t notice it that much due to where it is. As I said with exception of vertical warping (still near edges) i have to strain extreme left & right to really notice it. But it is still there slightly. It just is not that bothersome (adaptation).


Again - the argument is not about OP’s preferred headset. There are several parallel topics of discussion in the thread and none of them is about Pimax vs Index.

It all started with my surprise that people don’t make the most of their headsets (for example not getting the Index FOV on the old VIve with a thin padding) and mostly how common is to compare the FOV of the Index with the Small FOV of the Pimax. I honestly did not expect so many people play on Small…
And then the main discussion went into distortions - can you use the Large FOV without distortions or is it completely impossible and some people are lying to themselves.

Using small gives a bigger super sample budget which is just as important in sim racing, as is frame rate.

One of the problems in this discussion is that we are basing our observations and ideas on experiences with different games. I completely understand your point and completely agree that there are cases outside of my own use cases that would require different priorities when choosing an HMD. I already said so - it is all about personal taste and priorities. The discussion is not about that.

Also, I cannot accept the fact that someone can refer to the Large FOV of the Pimax as its greatest feature, yet the same person calls the higher refresh rate of the Index ‘unusable’.

I’m making some assumptions here. First I assume that for the effect to work the game will need to run in a stable way with the same fps. Otherwise people will still feel the effects of the reprojection.
I’m also assuming that for most people the resolution is more important than the frequency. This is based on numerous polls and posts inthe past years about what people generally consider important in VR (usually : 1. resolution, 2. FOV, 3. [something else, currently probably wireless]).
The third assumptions is that it is a zero sum game - in a very simplified way the choice everybody makes is between resolution and frequency (in the case of Pimax + FOV).
So in many games (that are more complicated to run than BS or SPT) running at 120 or 144 fps would require severe graphical downgrade. This is a sacrifice that almost nobody is going to make. For some of the most popular games getting and keeping those refresh rates is also simply impossible (modded Skyrim or FO4 for example)
What most people do is test their limits in dealing with reprojection in order to squeeze some more SS out of their system. The first thing that gets sacrificed is the frequency.
So - it will depend on the person and the games they play, but for most players and for some of the most popular games the higher refresh rate at this moment is not a meaningful benefit. As I said, this doesn’t mean that there are no games or people who will put the priorities in a different way.