So… Since before 8k/5k kickstarter units started shipping, concerns have been raised about the ability to adjust eye relief, especially given the canted screen design, where varying eye relief distance moves the lenses back and forth “past” your eyes to the sides, altering the whole projection setup - something that was never addressed; One could even argue that the “comfort kit”, that eventually came out, even made the headset less adjustable, clamping it in place, hard.
(And this should actually be expanded into more fine-grained, fitment adjustability, so that you could accomodate wide and narrow faces, and different cheek/brow depth relationships.
(Only ones I’ve noticed that may have addressed this somewhat are Varjo (if I understand what reviewers are saying about its collection of headstrap knobs right), and maybe Sony (I believe the PSVR may more or less “float free” in front of your eyes, rather than relying on the friction between one’s face and a gasket?)).
IPD adjustment alone can only get you so far, and even if they have managed to make new lens give you a clear view across the entire view, and from any point in the eyebox, hitting the sweet spot can still only remain optimal, especially to be right for the peripheral fresnel portion. (/me also think IPD adjustment should be separate for each eye, to accomodate at least horizontal facial asymmetry.)
So from what it looks like on video, we still have the “fried egg” design, basically with the difference that the “yolk” part is now collapsed into zero fresnel segments, instead of many, and it looks to me it is still biconvex, so we still have a transition area between the inner and outer zone - the distortion profile is not a smoothly contiguous arc, but a more complex spline, and we still have parts of the near eye surface, that slopes away.
I don’t know how many have seen Valve’s little logotype for their Index headset… It is a disc depicting an eyeball, in front of two half-discs, representing the HMD’s two monoconvex lenses, stacked, per eye (that’s not to say the lenses necessarily do have a spherical profile like the discs - they could be parabolic or whatever, for all I know - it’s just stylisation for the logo after all, but they are monoconvex - the side toward the eye is flat), going away from the hybrid design from the HTC Vive, with fresnel on one side, and a conventional lens surface on the other.
Whilst the hybrid approach let you use the front refractive surface to compensate for certain abberations, I do believe the simplifiction it is to get rid of it, probably has benefits in reducing pupil swim, as well as user-side reflections in the lens. It also lets you get your eyeball a millimeter or two closer to the lens… :9
We’ll see what Pimax come out with, and hey - maybe they will even have managed to suss out dynamic distortion correction, using the built-in eyetracking, but maybe it could be worth making a bit of noise about this whole thing right now, whilst there is a year to go, and there may still be time to in any way influence things, to prevent bad history from repeating… :7
(Wonder whether the maybe-prototype-but-more-likely-mockups people were wearing in the video are hand-sculpted samples, or CGI, or if tooling could perhaps already be done…)