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

5K+ has been my major headset ever since I started using it. It’s hard for me to go back to other mainstream consumer headsets even though the latter have better build quality, better support, and better comfort. Resolution and FOV are the most deciding factor for me, and the other headsets can’t satisfy me in those aspects. To achieve acceptable resolution and FOV, I am willing to accept some discomfort, inconvenience, and even distortions to some extent.

So I had not much interest in Valve Index when its specification is revealed. It looks not much better than Vive Pro which I can easily dismiss with my 5K+. My heart only jumped when I heard its perceived resolution and FOV are noticeably better than Vive Pro, and I bought one, headset alone.

Man I am converted. There is something that’s comparable to 5K+. The first thing I noticed is the perceived resolution / effective resolution. It’s almost the same as 5K+. I know some people think Index is a bit sharper than 5K+. I think this is because Index has better optics so it appears to have better clarity. 5K+ also has slightly bigger SDE. Still I think the effective information offered by both are about the same. I have compared them side by side with some test patterns. The details I can get from both are the same.

One interesting discovery: Index has the same “black dots” as 5K+! They are both more pronounced against red background. The “black dots” of Index are a bit smaller and harder to notice, but they are definitely there if you look for them. My advice: don’t look for them.

The FOV of Index is slightly smaller than the small mode of 5K+, but it’s still significantly bigger than Vive, Oculus, and Samsung Odyssey. Index has cleaner and more consistent view across the whole FOV, which is a big plus compared with 5K+. The image of Index is so nice and comfortable that I am willing to sacrifice some FOV for it. I feel I can wear Index for as long as I like, but 1 hour will be the limit for 5K+.

So Index is not in the same league of Vive Pro, even though it only looks to be “slightly” better. That “slight” improvement has made it go across a line, the line of “usable” and “not usable” for me after I have used Pimax headset, after which a headset must meet 2 criteria: Perceived resolution at least as good as 5K+, FOV at least as big as the small mode of 5K+. The FOV of Index is slightly smaller than the small mode of 5K+, but they are almost comparable, and it’s not claustrophobic at all. Considering the clear view across the whole FOV, it’s more pleasant to look at, and makes Index more usable than 5K+.

So Index has become my active headset for now, maybe until 8K X comes out. I have more and more belief that FOV is not everything. 110 degree is indeed not enough for 2019, but 130 degree is another matter. With superior optics and clear image across the view, it can beat a headset of much larger FOV but less consistent image. In an ideal world I’d dream of a headset of real human eye FOV and resolution, but we are still at a primitive age of VR, and we have to make compromise, and we have to think where the sacrifice should be.

I can’t thank Pimax enough for the joy they give me, and the push they give for the whole VR industry. They have also gained valuable experience in these years. I wish 8K X could learn from the lesson of 5K+ and 8K, and it could be a more mature and balanced headset of the next generation.


Could you please try to condense your thoughts a bit?

This was a very “streamlined of consciousness” type post.


You might be interested in @risa2000 hmdq tool.

I think part of the optics that helps a bit with sde on Index is the layered optics essentially providing 2 reflected screens per eye to view through.

So basically you didn’t get a DAS and the Index feels more comfortable and this is good enough reason for you to switch despite everything else.

What I find interesting in this kind of posts is how many people don’t care to make the most out of of their headsets.
Like the idea that the FOV of the Index is almost the same as the Small FOV of the 5k so it is OK. The only thing such a statement does is to make people wonder why are you playing on Small or even Normal FOV? The difference between the Index and the 5k (110 vs 170) is almost 1/3. It is better to conveniently leave the FOV from this kind of posts instead of writing thing like this.
And worse is the idea that the FOV of the Index is (meaningfully) bigger than the Vive. Even Valve themselves said that the FOV of the Index is the same to the Vive with a very thin cushion. In the first months after the Vive stared shipping the “sleeping mask mod” was very popular on Rediit. After that VR Cover released a thin cushion that has almost the same result.

I personally found it unpleasant and claustrophobic when I went back to the Pro (when demoing it to somebody) with the sleeping mask mod (so the FOV of the Index) after several months of using the 5k so I can’t imagine giving up 1/3 of the FOV for no real benefits. But we all have different tastes I guess. I have no problems playing with the 5k 7-10 hours a day, but the DAS is an important factor for that.


Of course I have the DAS. I might not have expressed myself clearly. When I say Index is more “comfortable”, I am not refering to the comfort of my head, but the comfort of my eyes. I have said in my post I am willing to sacrifice this comfort for bigger FOV and higher resolution. The question is how much we are willing to sacrifce. I am NOT willing to go back to Oculus or Vive even though they are more comfortable for my head and eyes, as their FOV is too small and resolution too low.

What I was suggesting in my post is that there might be some sort of line or threshhold of FOV and resolution. Once we go above that line, other factors (such as warp, distortion, eye strain) become more prominent and need more consideration. For me the line is the clarity of 5K+ and the FOV of the Small mode of 5K+. Other people might have their lines. We all wish the FOV to be as big as possible, but there are prices to be paid for this.

Why not comparing the Normal or even Large mode? An over simplified answer is they have more distortions, but there are other factors playing here as I have said above. If Pimax find a way to maintain the Large mode of FOV with the same optical quality as Index, I’d be in heaven.


Been playing with the Index since last night. My initial reaction was a bit muted since like you said the basic qualities aren’t that MUCH better than the Vive Pro/5k+ and then there’s of course the glare. However I’m starting to appreciate the Index more and more. The stability of the virtual world, the feeling of depth, the feeling of immersion, the geometry correctness, the sharpness and of course the audio, it all adds up to what I now think is just the best VR experience that money can buy. However I do keep thinking that Valve should have gone with those 2k*2k panels, that would have made it the best headset for quite a while to come.

Anyway this also makes me more skeptical of the Pimax 8k-X. I mean I’m sure it will have the best specs ever but VR is just so much more than just the specs, that’s what the Index really proves. I just don’t believe Pimax is capable of delivering that.


First I need to say I’m not reacting against your decision to downgrade. I’m reacting against statements that I believe are incorrect or misleading.

I am NOT willing to go back to Oculus or Vive even though they are more comfortable for my head and eyes, as their FOV is too small and resolution too low.

The FOV of the Index is the same as the FOV of the Vive with a thinner cushion.

The resolution of the Index is the same as that of the Vive Pro.

they have more distortions

I have been following Reddit and this forum closely and I have seen the complaints about distortions dying down. I personally have no distortions on large FOV and I think this is mostly because of the thicker Vive face cushion I started using (on top of the software updates). It seems Pimax have been sending different cushions to people so we have different experiences with that.
The other part of this is the IPD adjustment. My current way of setting my IPD is to open Beat Saber and start looking around while adjusting the IPD until all curved lines become straight.
The software IPD settings have been confirmed to fix the issue with the eye strain for people who experience it.

I see somebody just posted a comment complaining about " the feeling of depth, the feeling of immersion, the geometry correctness" that are the exact symptoms of incorrectly set IPD.

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Be interesting to hear how 8K users compare it.

Initially the 8K was blurry but with the Vertical Screen Adjustment, it is much better. The Pentile Screens do still fuzz out the image but texture detail can be quite vivid at high Render Resolutions.

I tried recently the 130 FOV option in PiTool for 1. to see how it looked and 2. Performance over Normal (150) and Large (170) FOV. To be honetst, on both counts with FFR - it sucked. The view felt straight Jacketed and there was no speed benefit at PiTool 1.5 with SteamVR 100% over Normal FOV. Large FOV is to be tested when the SteamVR 8192 limitation issue is fixed in the next version of PiTool.

FFR seems to really benefit larger FOV where the periphery can be much lower resolution to the Sweet Spot Center of the Lenses. Hence no real benefit when you just cull the periphery with the small FOV.

Glad I didn’t jump on the Pimax 5K+ bandwagon when it was offered but stuck with my 8K. Looking forward to what they bring to the table with the 8K-X.


Well it is only a downgrade in terms of:

  • FOV
  • glare

Better in the index are:

  • colours & contrast
  • sharpness/details
  • 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

Overall the Index results in a much more pleasant VR experience than the 5k+ in my opinion. Of course everybody is different and if FoV really is that important to somebody, then the 5k+ might be the better choice.

If Valve would just add higher resolution panels, I’d be in VR heaven. I’m still pissed they didn’t go with those 2k*2k panels, damn that would have made it a KILLER headset.


But look at where HP Reverb is. They chose the 2k x 2k route and eventually pulled the HMD from sale as far as I can see.

Then there’s the demands if you go wireless. We don’t know yet if Intel are working on a wireless system for Index but I think 2x2k is too demanding.

There’s nothing to stop Valve making an Index+ next year when quality panels become available. But for now they just need to get the price down and volumes up.

Yeh I have the same disappointment when it was reveal that Valve has not gone 2k2k. I still think this is a critical mistake for a premium headset of 2019. I have a Reverb and the clarity is stunning. It’s a pity Reverb has such a small FOV and flickering issues. 2k2k plus the current FOV of Index and superior optics and other build quality would make Index a real killer for VR fans. I can get higher framerate on Reverb while maintaining sharper image than Index as Reverb needs less supersampling, so performance is not an issue.

I still think 8K X is our only hope for higher resolution and bigger FOV for the coming year, as Oculus, HTC, and Valve have all just turned out their “nextgen” headsets. All the more reason why previous lessons should be taken seriously.


As an aside on the topic of perception/value thresholds, I have come to form an impression that - at least in terms of that mystical property: “presence” - every degree of extra FOV is not linearlly equal.

I’d say that up to 130°-140°-ish all expansion of FOV is of immense value to presence, but then the value per added degree begins to flag for a while - still an improvement - just not as great, until you creep closer toward and past 180°, where the increase in immersion “accelerates” again, producing something of an “s” shape curve.

Your mileage may vary, of course.


You really need to tune in your IPD settings correctly.

colours & contrast

I have seen contradicting impressions. There were quite a lot of “dramatic” posts on r/skyrimvr by new Index users. LCD is LCD… At least Pimax gives you control over brightness and contrast.


A point of view. I personally consider the leaky audio a con for somebody is who is living in a city like me. This type of audio would be great for an AR headset, but a terrible idea for a VR one.

software/ease of use

I honestly don’t understand what is so hard to use with the PiTool.

Build quality

As a VR tech enthusiast this is one f the least of my priorities in this stage of VR. What matters is innovating and pushing the technology further. And unfortunately Valve played it really safe.
By the way I have the 5k for 7 months now and I haven’t notices any issues with the build quality. So far, for me, the worst headset in this regard is the Vive Pro that is making cheap-plastic noises when I move my head abruptly.

refresh rate

The only actual benefit of the Index. However with the current level of hardware support mostly unusable.

Even if you combine all the small benefits that the Index has they are still not enough to compensate for the 1/3 less FOV. Even if you are not a FOV maniac this is still a big downgrade.


Pimax headset is actually just a touch over 160 in large FoV. Try Risa’s hmdq tool as it gets the requested info for render FoVs.

Yanfeng is also a close friend of the pimax team & was an m1 tester. As a result he demonstrat3s a high level of integrity by providing honest feedback. Pimax headset does have some benefits for sure. But unfortunately for some Eye strain does occur due to the design trade offs. I fortunately like @Lebois not in that camp.


There is still distortions especially the geometric distortions near edge of FoV. Granted these are less in the 8k vs the 5k+. Just like sde some adapt easier than others. For me it’s more straining to twist my eyes that far in left to right to really be bothered by them. Up & down has them to q degree as well.


Believe me SJ would have his set correctly as he modded his old p4k to better accommodate his large ipd. Simply some are more sensitiv3 to distortione tham others.

Audio the open ear I can see pros & cons to with design.


The point Valve made when refusing to specify an “official FOV” for the Index was that it can depend on too many factors. Did he say what are his results for other headsets?

Here is a measurement that Steve from VR Roundtable made. I don’t think the numbers themselves are important, but the relation between them - measurements made by the same person the same way. Index: 108; 5k Large: 162 - still 1/3 difference.

Believe me SJ would have his set correctly

I have been playing Skyrim a lot on Vive, Vive Pro and the 5k and there is no difference between them in terms of geometry and feeling of depth. And this is a game where it would be obvious. Those problems are however almost always a symptom of an incorrectly set IPD.

Up & down has them to q degree as well.

I have never seen vertical distortions when the IPD is correctly set. And I currently have no distortions all the way until the very edge of the lens - where it connects to the black plastic. After putting a thicker cushion for me the distortions have been sign that the IPD has moved so I tweak it again until all straight lines look straight. The distortions are the best way to guide you during setting the IPD up.

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Risa’s Hmdq tool uses only hard Data, not Perceived FoV which is misleading & true at the same time.

Yea he has reaults for other & yes from my understanding it even checks inputted setting.

Perceived FoV is affected by a variety of facters especially potential of ipd. First HeroVR rate FoV as a variable if mem serves 150 to 170.

As long as we agree that the FOV of the Index is 2/3 of that of the 5k I’m happy to call it whatever you say :slight_smile:

I think there are two aspects to that.
The first one is the game you play. In a game like FO4 every degree counts (I would imagine the same for the MP shooters). Those are games where the peripheral vision matters a lot. Another example is Audioshield - on higher difficulties the balls come more from the sides and it was a relief to be able to play without constantly looking left-right-left-right…
The other one is the “conscious” immersion vs the unconscious one. I remember my first reaction when I put on the 5k. It wasn’t “wow”, it was the feeling that now everything is right. It was like a pebble was removed from my shoe - something that was bothering me was now fixed.


…which is precisely why I decided to qualify the statement with the “presence” thing.

Obviously every extra degree of FOV is one extra degree within which you can spot a target to your side.

I didn’t have your revelatory experience with the P8k/5k, though: The 160° “large” option FOV was niiice, by any means, but still fell (…and still falls…) utterly short of diminishing the “diving mask effect” – to me.

Obviously I do not have a full human FOV headset to make implied subjective observations with – this is experiences with shading parts of my real world field of view.