PSA: Reverb G2 small sweet spots, observations and solutions

Hi,

I wanted to start this discussion because like many others, I’ve been underwhelmed at first with the G2 “sweet spot” and I believe there are solutions like the one I’m describing below.

TL;DR: The Reverb G2 seems calibrated for a shorter focal distance than other headsets.

I can’t see up close but can see farther away (do you call it nearsighted or farsighted?) and I’m usually wearing reading glasses. Because HMDs are usually calibrated for displaying the image at roughly 2m which I’m conformable with, I don’t wear glasses with the Index and it is really fine. Once I’ve tried the G2 I constantly was feeling something odd with my vision like eye straining quite quickly and as if I had strabismus. Another odd things I’ve noticed is comparing side by side the Index and the G2, the image is appearing smaller to me in the later.

I’ve therefore decided to experiment with something: I’ve purchased low costs +1 reading glasses at the local pharmacy. Results: instant eye strain relief, clear and sharp center with the impression of a wider sharp cone in the center (it is still fuzzy as you go toward the edges but it is not appearing as much as a “clear cut”), and to top it all it is also solving the newly added WMR Anti-CA filter* which was wrongly separating the R,G and B layers too far apart otherwise. White lines are now white from top to bottom.

NB: my correction is usually +2.5 both eyes (about), and this is where using +1 does the trick: it is just a magnifying glass which makes things clear to me at about 1.0m to 1.5m distance, whereas I usually see clear past 2m to 2.5m. In using this small correction this makes my eyes focusing correctly on the virtually projected image of the G2 panels and this seems to correctly put the focus at the designed distance for which they are calibrating the G2 lenses and the WMR anti-CA pre-processing filter.

For 15$ or so, not bad at all!


*Anti-CA Filter: any lens is creating chromatic aberrations (CA). This is due to the physical nature of the light traversing different medium and diffracting light to different directions depending on the wavelength. You can mitigate some with a complex lens system like in Multi-Element Reflex Camera Lenses, or, you can mitigate by software in doing the reverse operation. Usually you might be accustomed to CA correction in pro photo, where you’re correcting by software the CA in realigning the R,G and B planes separately.

The latest(s) WMR includes an Anti-CA filter. What it does most likely is doing the reverse of the CA correction, that is un-aligning the R,G and B planes so that once the light traverses the lenses, the diffraction effect will make the 3 coinciding again:

non filtered:
white bar -> light -> lens -> diffraction (creates R,G,B fringes) -> separate colours displaying
with filter:
white bar -> filter (creates R,G,B fringes in reverse) -> light -> lens -> white bar displaying

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Glad to hear reading glasses or a + diopter lens can solve much of the blurriness problem with the G2.

About a month ago I reported a similar finding while playing around with kiddie smartphone VR goggles. I am 75-years-old and have age-related presbyopia (inability to focus close up with hardening of aged eye lenses) and replied to a poster who claimed because of the optics in HMD VR goggles presbyopia was not a problem.

One thing that I have read is that inserting an additional + diopter lens between your eye and the lens that comes with the goggles reduces the overall field of view. Do you find that with the HP Reverb G2? If so, any guesstimate of how much?

Since your presbyopia correction for very close-up is about the same as mine, have you tried a +2 diopter? I haven’t tried a +1 lens yet in my smartphone goggle test but for +2, based on the outstanding clarity of the screen door effect that I got playing with an iPhone 6S in the kiddie goggles (!), I thought the +2 would work well.

BTW, for + diopters, the diopter value is roughly the reciprocal of the distance in meters that a lens of that power allows you to focus on an object. A diopter of +1 allows you to focus on an object 1 meter away. A diopter of +2.5 allows you to focus on an object 0.4 m (~16 in) away. I would think to see the image in a VR headset, you need to clearly see the pixels on a screen several inches away from your eyes, so the ideal diopter would be closer to +2 than to +1. If one were not focusing fairly close up on the HMD’s, where would the screen door effect in some VR headsets come from?

Thanks for any additional comments on what the added diopter correction does to the available field of view. Since the diopter correction works for an HP Reverb G2, looks like a G2 may be in my future (didn’t want to lay out myself $600 just to find out if reading glasses inside the G2 would deal with my serious presbyopia!). And if the reading glasses are good for me, I will probably pay additional bucks for prescription lens inserts to deal with my mild astigmatism that the reading glasses will not correct. My normal glasses do not help as the bifocal correction there is graduated across the field of view, greatest towards the bottom (looking down while reading), least straight ahead.

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One other (and much simpler) suggestion:

I really struggled with the sweet spot until I saw a YouTube video explaining the proper way to put this headset on. Not like a baseball cap. The bottom strap on the back needs to go below the back of your cranium, where it starts to curve back in toward your neck. Only then should you adjust the headset itself to get the sweet spot into the center of your view.

I don’t know why this works for me, but if I try to wear the headset like my old rift (strap around the middle of my head), I can’t get it adjusted right no matter what I do.

Give it a shot.

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@CurdledTree18 Of course you are right, the first step is to properly wear it to get started. But once you do, and you know how to wear headset, and you can compare it with other headsets like the Vive and the Index… Add a little bit of knowledge about optics, and I’m nearly certain, from the eye strain (and relief with +1) and the Anti-CA not working unless compensated with +1, that the G2 is either designed for people without any vision problem at all, or thinking in reverse, the reason the G2 gasket is so much recessed to the point there is the Frankemask, is because they’ve designed it first and foremost for people over 40 wearing reading glasses…

@JALxml Your explanation on diopters fits with my experiment! The +1 over my naked vision is just what was necessary to get the focus at the right spot and to eliminate the Anti-CA filter induced fringes and getting edge to edge clarity (it is not 100% clear from left to right, the farther from the center, the blurrier of course, but this let me read text for example up to about 60% off the center compared to about 20% without the +1 glasses).

I’ve also tried +2 (same cheap reading plastic glasses) but they were too much for my vision. As for FOV, honestly I don’t feel any particular loss. The G2 has room to wear those cheap glasses and I get about the same FOV I’d get with the Index and prescription inserts most likely, because in the later case you’d have to make room with the eye relief adjustment.

As a comparison, I can wear the Index with the lenses nearly touching my eyes and have no focus problem and therefore, the largest FOV (it is really good and when using TAA60 + SS220, I have a really great experience in FS2020 - except with EFIS for which I have to lean over but superb in GA*)

*I shall add: when I say “superb” it is not like I’m being in a real aircraft at 120fps… superb all things considering given the actual VR tech available and the mid-range 2070S I’m running my test system with…

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Following this thread with great interest…

Years ago (when I turned about 40), I started using simple reading glasses while using my computer monitor. I believe I worked up to a +2.5 eventually, before I finally got my eyes tested professionally. It was then that I realized that I also had a problem with distance vision a bit as well. For example, while at the doctors office I discovered that although I could see the screw in the light switch across the room, it wasn’t until he tried some correction that I could then actually see the slot in the screw and which way it was facing. The results were that I was given (my sister worked there) a very expensive pair of “progressives” that do an outstanding job both near and far.

The problem I have now, is… what good are progressives inside of the G2? Focus changes looking through either the top or bottom of my glasses, but that’s not where the sweet spot is. I assumed that I might need a simple pair of reading glasses again, just like working on the computer before, but I wasn’t sure if I needed to start with the old +2.5’s again. If I understand correctly from reading the above, the G2 is designed with a focal point of about a meter?

I guess I’ll pick up a pair of +1’s first and try them inside the G2, and go from there.
Turning 60 this year just sucks.

Jim-Sim

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I ended up keeping my G1 after testing the G2 with various sim VR cockpits (especially tubeliners with EFIS PFD and NAV_- I just couldn’t get enough clarity away from center. I would have thought that they would basically keep the same lens parameters from the G1 but somehow the design changed.

Thanks for a great, reassuring answer. Perhaps the fixed far-distance lenses that replaced my natural eye lenses with zero ability to be focused close up explain some of the diopter differences And perhaps a different eye-to-screen distance in the smartphone VR goggles and the way my wife’s full-frame +2 OD reading glasses sat on my nose had an effect, too. I recollect now that I did try the Foster Grant Braydon trifocal lenses that I wore during cataract surgery recovery and the trifocals are +1.25 OD in their lens centers but that didn’t seem to help as much as the wife’s +2’s. Great to know that the field of view is not noticeably affected. Also, since I too just have a 2070S in an i9-9900K, 32 Gb RAM, 1 Tb EVO 970 Plus, it’s great to know that a 2070S is enough for a relatively “superb” VR experience.

On the distributor’s website that HP has picked to handle G2 pre-orders, down at the bottom under DISCLAIMERS, item #1, it states:

  1. Interpupillary distance (IPD) adjustment is included. Eye relief is not a feature of this product .

I took that disclaimer to mean that the headset optics assume you have perfect or otherwise corrected vision when worn and it’s up to you, if not, to figure out how to accomplish that suitably. Great!

I’ve seen several articles recently that Apple has several patents on accommodating prescription correction in HMD’s. Most of the articles point out that filing patents don’t mean a whole bunch about anything ever coming to market. But it would be funny, if just like the iPhone, Apple in its way of working quietly on things for years, catches everyone by surprise. Apple Invents a Hybrid HMD System that Supports Prescription Glasses in a very unique Manner - Patently Apple

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I bought one of those custom prescription lenses that are on the market now for the G2. Mine are from Widmovr, though I’ve noticed a few stores offer them now. It’s improved the experience greatly - I get much better clarity than with my glasses, though they are the same prescription (not to mention the comfort level of not having my glasses under the gasket).

I haven’t done too much flying in MSFS pending performance improvements, but in IL-2 I can glance down at most of my gauges to quickly check them without moving my head. I can get the center perfectly sharp, and it does fall off a bit on the edges with a bit of chromatic aberation, though as I stated unless there is a particularly small gauge or tiny text, I can read the value of most of them even at the edge of the FoV. Note that as this is in IL-2 that I’ve spent most of my G2 time in, these are steam gauges. I don’t like the G1000s in MSFS even on a monitor.

I’m near-sighted, so I’m not sure how this custom prescription lens solution would work with those who need reading glasses, but this purchase was well worth it for me.

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I’m definitely going to give this a shot as well. The FOV in my Rift S wasn’t hot, either, so my frame of reference (pun intended?) is different. I have indeed noticed more eyestrain with the G2.

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I’ve been hunting around for good, detailed explanations of the optics in VR headsets and this inreality.com wiki page is the best summary explanation that I’ve found. Basically, what’s going on is the real life headset displays are only a few inches from our eyes but our eye lenses can’t focus on anything that close. So the optics turns the nearby display images into a set of virtual display images that appear to be about 1.5 m or more away. And then I think the deal is when your brain processes two separate stereoscopic images that it can clearly see 1.5 m or more away, parallax differences, size differences in objects in the two 2D images, etc., induce your brain to recreate a 3D version of what you’re seeing. And as you move your head or move through the virtual world, the corresponding changes between the two images, one for each eye, generated by your computer and gpu, keep that illusion going just fine. So if you’re like me or CptLucky8 and need some diopter correction to see things clearly around 1 to 1.5 m in real life, you’ll probably need some optical correction to see things clearly with a VR headset that has a relatively short focal distance for the virtual screen images. Perhaps the difference in corrective diopter that CptLucky and I found worked (+1 for his presbyopia, +2 for mine) could be attributed to differences in the lens focal lengths for the G2 headset he was using vs my El Cheapo smartphone VR headset… as well as differences in our presbyopia, etc.

The references cited on the following wiki page are pretty good to go along with the article. In particular, reference 4 is a YouTube video illustrating the creation of a virtual fly image further away. Reference 1 provides even better illustrations and a better accompanying description than the wiki article.

I’ve probably got wrong some of what I wrote - still an ignorant newbie

Virtual Reality Headset Lenses - Virtual Reality and Augmented Reality Wiki - VR AR & XR Wiki (xinreality.com)

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I’ve been using prescription lenses from the same company with my Rift S, and the difference is amazing. I have the Reverb coming tomorrow (hopefully) or Monday at worst, and will be trying the same thing with a set of lenses I ordered for THEM!
Anyone who has glasses - do yourself a favor - GET PRESCRIPTION lenses! I am a DCS F-18 driver and I wouldn’t even think about flying with just my glasses on, even though they do fit in the Rift S. The difference though is night and day - clarity, sweet spot, chromatic aberration, comfort - the works.
Interestingly enough, if your’re NOT a glasses wearer, you shoudln’t have sweet spot issues though… It’s not like you need glasses to improve your sweet spot!

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What my Index (or G1 or Vive) vs G2 is showing clearly (pun intended) is this also depends on your correction and headset. If you need reading glass (typical over 40 years old) you can still wear the Index without any prescription if you can see ok beyond let’s say 2m to 2.5m. However with the G2 you can’t because it is as if their focal distance is much closer within your “I need reading glasses” range, and I didn’t expect they’d calibrate their optics this way because honestly, most person above 40 will have a bad experience with the G2 from the get go…

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A couple of people have mentioned WIDMOvr for prescription lens inserts. Would be great if other folks as they add comments about reading glasses or prescription lenses mentioned the brand of glasses or source of prescription lenses - might help the rest of us as we try things and shop for the best solution if we get a Reverb G2 and feel that we need some additional optical correction. Although $15 full-lens reading glasses might be considered generic, if any lens coating or lens thickness makes a difference, brand could matter a bit. Would be interesting to know, too, if there is much danger of scratching the out-of-box G2 lenses when wearing glasses of whatever sort - a reason to steer more towards prescription lenses, perhaps. This thread has definitely encouraged me to take the plunge for a G2 and alleviated optical anxiety (a new medical condition!). :slightly_smiling_face:

P.S. On any comments about prescription lens inserts for the G2, I’d like to hear opinions about the value of going for high refractive index plastic and on the anti-blue light protective coating if folks have tried either of those.

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Can I ask how the reading glasses/diopter interact with or affect any prescription which you may need?

I’ve worn prescription glasses for a year or two (mostly when working on a screen but not all the time) but don’t really know much about the subject, to be honest.

If the +1 diopter of reading glasses is helping with the sweet spot, can this be “added” to a prescription lens, such that if I were to order inserts from WidmoVR, VRoptician, etc. I could get the right “corrections” as per my eye glasses along with the additional “reduced” focal length which the diopter applies?

Thanks!

@wheeliemonsta I believe you got it reversed. VR Optician or similar inserts vendors are taking your actual prescription and build the glasses accordingly. You shouldn’t change anything to your prescription in this case.

I’ve tried +1 whereas I usually need +2.5 (a little less in fact) because this is just what is needed to make my eyes being able to focus to the distance the headset lenses are virtually projecting the screens to.

Please note my cheap glasses trick is an experiment in order to try validating whether there is an inherent flaw in the G2 small clarity circle or if it its optics are different than the other headsets I’ve tried to the point I can’t wear it without any sort of correction. The advantage is that it is cheap to try and there is room for the glasses in the G2 (I’ve chosen a glass model which would fit with the largest plastic lenses I could find (I think these are Foster Grant) and which I can unscrew the lenses from the glasses if I ever want to make a custom cheap insert of some sort. Ideally I’ll wait until I can get an appointment with an optometrist to get an updated prescription for my current vision correction and most likely go the VR Optician route for the G2 in the end. With the pandemic, you have to be patient sometimes.

NB: I’ve tried again the Index yesterday to see what about the +1 and I must admit it helps focussing a little better to for me, but not as dramatic as the difference with the G2.

PS: actually I’ve been always wondering about what companies like VR Optician are doing with the prescription: are they making glasses with the same correction or are they “subtracting” the HMD lenses to the prescription. I believe they do the later otherwise I can’t see how this could work.

TL; DR The short answer is that the SPHERE correction, the 1st column in a prescription is the diopter correction needed for distance vision. If it’s negative, you’re near-sighted. If it’s positive, you’re far-sighted. The ADD column, further to the right in a prescription is the diopter correction needed for close-up vision when your lenses have hardened and can’t be compressed to focus close-up. The ADD diopter is always positive (because you are ~“far-sighted” for near vision if you have presbyopia). Usually the ADD diopter is a correction for about 18 inches of viewing distance. The effective diopter needed for viewing, if I got it right, would be your SPHERE correction added to your ADD correction. So if you were pretty near-sighted, -2.5 SPHERE and +2.5 ADD, you would need a 0 diopter correction to read 18 inches away and be able to read small print on a medicine bottle perfectly without your glasses, if you don’t have significant astigmatism, which complicates things. But the virtual display images for each eye in VR goggles are not set to be 18 inches away from your eyes.

Question for anyone with a filled prescription lens for VR goggles: Did anyone get back from the prescription lens company the actual optical parameters for the lenses made? Would be interesting to see the prescription submitted to the lens company vs. the returned VR lens parameters. Please post if you have that so the rest of us can learn from it, along with your opinion of how well the prescribed VR lenses work in your goggles. I think that I will go with a company eventually that promised to provide the manufactured lens parameters to me.

Long-winded version of how presbyopia factors into everyday vision and VR goggles: For every day glasses, the correction needed for presbyopia is usually placed in the lower part of the lens of the glasses for each eye - the upper part of the lens is for straight ahead distance vision, the lower part is for closer to close-up vision. You’d think a person would get confused but the wearer quickly learns to reflexively move one’s head without thinking about it to have the head at an angle to the desired line of sight to be able to look through the right part of the glasses. For presbyopia, because the eye lens has hardened with age, your eye muscles can’t squeeze the lens to focus it a differing degrees of nearness the way a younger person’s eye can. Therefore, having bifocals for very close-up and distance vision is a black-and-white hack that leaves out intermediate distances. This problem is addressed by having trifocal glasses or even better graduated bifocals where the amount of presbyopia correction increases from the middle section of the glasses towards the bottom (this type of prescription is the most expensive but the best). The wearer again learns to use graduated bifocals with reflexive head movements to get the clearest vision for a desired viewing distance without even thinking about it.

With an HMD, depending on the OEM, the virtual display images are moved far enough from the eyes that a normal seeing person should be able to focus their eye lenses on the images and see them clearly. I think I read on the web that the original Oculus Rift virtual images were effectively at infinity - where presbyopia, the inability to focus close-up, wouldn’t matter. As CptLucky8 points out in his OP, newer headsets have reduced the virtual image distance to 2 or 3 m, effectively, or less. The closer the virtual image is to the eyes, the more presbyopia correction, if needed for real life vision, factors in, and CptLucky8 suggests for the Reverb G2, based on his presbyopia, he figures the focal distance for the G2 is effectively about 1.5 m.

So if you have presbyopia, when you put on VR goggles and the virtual image isn’t all that far away, you’re going to need some presbyopia correction, and real-life glasses are not going to do the trick, especially if they’re graduated because the amount of presbyopia correction will vary according to what part of the lens you’re looking through, designed for different distance viewing, whereas let’s say the virtual display images for the G2 are effectively always 1.5 m away no matter where you look in the FOV. So therefore you might need the same diopter correction for all parts of the display that you want to look at.

In drug stores and Walmart there’s a reading glasses section, often near the pharmacy section, probably to discourage enterprising customers from just donning the merchandise and wearing it out of the store. There are part-frame and full-frame reading glasses of various diopters and a test reading chart whereby you can check out how well with a particular diopter you can read small print close up. If you wanted to try a diopter correction via reading glasses, you wouldn’t want to stand from the chart at the typical reading distance, about 18 inches or so, but stand away at the distance that you think the virtual display might be set to appear.

The problem with using reading glasses is they might not fit in the headset. If the lens abut the built-in lens that the VR headset comes with, the glasses lenses might scratch the VR lenses by rubbing against them, and if you also have astigmatism (non-spherical eyeball), the reading glasses won’t correct for that.

Theoretically, prescription lenses could correct for both presbyopia and astigmatism and obviously avoid the goggle fit and lens abrasion possible problems as they replace or go over the lenses the goggles came with depending on the options for a particular brand and model goggle.

The thing that I don’t understand having looked at several VR prescription lens websites is the blurbs on the website say that the lens made usually use the far distance correction in a prescription, which is not what a presbyopia sufferer wants - you want the appropriate near-distance presbyopia diopter correction to be factored in in addition to the far distance correction just as you would for a regular glasses prescription when looking through the part of the lens designed for intermediate distance viewing.

I asked one of the online sellers about presbyopia correction and got a less than satisfying answer - suggesting that they only planned on going by the distance vision correction and if I felt I needed a presbyopia correction, I’d have to give them my preferred prescription! That’s why I’d love to know, as I requested in a previous post, who got the best satisfaction from what online VR prescription lens seller, particular if the poster needed presbyopia correction. BTW, the response below is from VR Optician - maybe the “front desk” folks are not the same as the guys/gals in the back who actually make the lenses (one would hope!):

We really need oly the far
distance prescription for the adapters. But the best soulution would be
if you test it before. When the headset arrives you can try out if you
like it better with or without reading glasses and the order the values
you feel/can see best with.

Here’s a WikiHow description of how to read your prescription. Any needed presbyopia diopter correction would appear in the ADD column: How to Read an Eyeglass Prescription: 11 Steps (with Pictures) (wikihow.com)

Foster Grant sells “Multi Focus Reading Glasses” with 3 basic diopter corrections for close-up reading, computer screen reading, and across-a-desk viewing. Foster Grant Multi Focus Reading Glasses - Foster Grant.  If you have a base diopter for close-up reading of +2.0, jlacroix of Foster Grant explains in a blog post answer June 23, 2015(see down the page) how the required diopter might change for those increasing distances, according to Foster Grant’s calculations:

Simply put, when you are purchasing Multi Focus readers, order them in the closest diopter you can to what you currently use. The middle area is reduced by approximately half of a diopter from your “base” diopter and the top diopter is approximately one half the strength of the “base” diopter that you order by. IE If you order a +2.00 the 3 areas will be approximately the following diopters:

Top: +1.00
Middle: +1.50
Bottom: +2.00

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+1 for this. I don’t wear glasses, but I frequent the Oculus and Index subreddits. It’s very common to see posts from people saying they scratched their lenses (and their glasses). So be careful if you aren’t using some type of insert.

Does wearing glasses in a headset have a noticeable FOV loss? I always figured I would try to get contacts if I ever needed some type of corrective lenses in case of a lower FOV.

Speaking of what I learned on Reddit, don’t ever let your friends use your headset because it’s inevitable their hands will break your monitor.

So do I…G2 went back ;-(

The best discussion I’ve found so far on how diopter correction for presbyopia interacts with the rest of your eye prescription and is adjusted for varying distances is in a blog post by one “Julie,” who lists no credentials beyond that she has worked “in an eye doctor’s office” (under the About section of her blog). How To Determine The Strength of Reading Glasses You Need - Contacts Advice

She presents a table on how the ADD diopter, which she indicates is for a focal length of 40 cm, should be adjusted for increasing distances:

So jlacroix of Foster Grant (quoted in my previous post) might be a little off in explaining how Foster Grant’s Multi Focus reading glasses work at increasing distance - another front desk person who doesn’t fully know what’s going on in the back?

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