Very nice compare pics. 
With good detail on measures!
Mmmmmm I don’t have any plans to order a Valve Index but would take this diagram with a pinch of salt.
On reddit the author is taking a bit of flak where he states “For Valve Index i just draw 5 degree, lense dimeter is same as Vive. It’s not exact measurement, just example…”
Is this confusing hp reverb with valve index? I ordered index and technically it should be just slightly smaller fov than pimax normal mode. Will get the reverb next week, 114fov not index
Valve hype train lies about FOV (not Valve - they never say aboout 130). Valve Index have optimezed Fov like Vive with ultra thin face cover but far away from Pimax Normal Mode.
130 Diagonal maybe?..
Sounds like you are just making things up. The way it works is based in part to your face shape and IPD/ Just like Pimax, The display have greater adjustability than the pimax to set the optics closer or further away from your eyes. Not it wont have the same level of FOV as Pimax for sure, but it is quite cleat that is indeed larger by hands on accounts.
Look I get it you own your pimax and you are biased, and that’s OK.
+20 degrees from t5he 110 of the Vive. Norm hinted that is for sure horizontal as he said that know the full theatre image is within his view unlike the tunnel vision of the Vive and similar headsets
HTC Vive have big FOV 110 degree, is really big but no one dont see it, If you want see it you should wear this without face cover at all.
Valve give you this adjust - and canted optic give you 4-5 degree more.
FOV hype about Valve is about eye to relief adjust.
I think big improvement for Index will sweet spot, sometime full 110 degree with sharp edges better than 140 degree with blurring edges.
But Valve not 130 FOV just believe. No one understand about real FOV.
In overall lens diameter its major limited factor for FOV, and Valve give only 50 mm like Vive.
Look, this is all we know. We have not tested it and anything is pure conjecture at this point. I will get a first badge of Index Units. Will likely make a thread after I test it
If you have HTC Vive just measure your FOV with stock face cover and without face cover at all and you see difference.
Just subscribe and change SteamVR background.
Yes, Im aware of the FOV testing. Wont get my unit till late June
OP’s 15 mm eye relief seems excessive to me, but I must point out that Valve’s rather deceptive wording is not: “20 degrees more than the 110 of the Vive”; It is “20° more FOV than the HTC Vive for typical users”.
From what I have only too often read people writing, it appears “typical users” of any headset do not do anything to adjust their eye relief for maximum FOV - a lot seem to pick up the impression that the Vive has no more FOV than the Rift CV1, and, on top of that, do not notice the reduced stereo overlap in the latter at all, which suggests they are restricting themselves to much less than either device has to offer.
If you wear your Vive so closely that you can see the notch, where the bulging (lens pincushion distortion) inner edge of the screen cuts into the view, which you will if you’re getting 110°; Then you are probably not what Valve considers to be a “typical user”.
People really need to temper their expectations.
EDIT:
EDIT2: Hmm - hadn’t drawn that diagram before. -There is plenty of potential room for stereo overlap, it seems, somewhat quelling my worries in that regard, provided Valve has actually put screen all the way to that inner edge… (…at the cost of PPD, of course. Now, if the two-element lenses distributes pixels more evenly that the Vive’s older ones (there are indications to the contrary, alas), that ppd hit could be less bad, than it would othewise…)
It’s very possible you are right - but if you are going to call people lairs then you need to back it up with empirical evidence. So far I just see guess work, do you have evidence of the Valve index FOV?
Ah that’s not a good sign 
Variable FoV relief Knob. Up to 130° says should for most give up to 20° more FoV.
yup seen it. thanks man
this is really informative. keep it up! 