Index virtual focal length?
Does anyone know what the approximate virtual focal length is for the Valve Index? In other words at what distance is the Index requiring your eyes to focus?
Posted Aug 25, 2019, 6:19 AM UTC
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Further than the Vive. Around 1 meter. At -1.5 diopters I didn't need corrective lenses for the Vive but I do for the Index. Using the 3d printed prescription lens adapters w/lenses from Zenni.
https://www.reddit.com/r/ValveIndex/comments/ceorjg/3d_printed_prescription_lens_adaptor_for_valve/
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Yep I didn't need anything for the Vive either, unfortunately I do for the Index as well. I'm a little puzzled how the two main VR lens companies are taking standard prescriptions (usually for very distant focal lengths) and having them work well with what appears to be a ~2m virtual focal length with the Index. I'm assuming it's "close enough" for most. I know my "distance" glasses aren't quite sharp at 2m so I have some mid vision glasses, mainly for coputer work, that work well at this distance.
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Generally the eye muscle is supposed to be flexible enough to cover the full range of near to infinite if the lens is corrected to a "normal" starting strength (the same as with uncorrected vision). Usually it's only as we get older that the lens becomes less flexible and our eyes can no longer do the full range, at which point bi/tri/progressive lenses become needed. Or sometimes distance correction is no longer needed but reading glasses become needed.
Anyway I know a bit of what you mean, my prescription sunglasses are actually -1.75x and while I can use them for all distances, they're best for driving as my eyes will feel a little tired after extended usage at close distance (but no problem with 12 hours of driving). Of course I pass 20/20 vision tests with -1.5x lenses so it's not necessary, but it's a nice bit of extra sharpness beyond required.
Also part of why I prefer glasses over contacts: after trying making variations with my doctor, they could never find a strength that matched the distance clarity of -1.5x without also tiring my eyes out for computer work. Only going to -1.25x would avoid that, but then distance felt not sharp enough (even though again, I would technically pass driving vision requirements) compared to what I was used to. Normally I don't even wear glasses for computer use.
Anyway, yeah, your point is good, for most comfortable use, your VR prescription lens adapters should be whatever strength you'd find best for ~1-2m, but generally our eyes are flexible enough to make an "infinite" distance prescription work at that range.
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Yo. Just got a camera with HDMI out and focus peaking today, so I did a similarly trashy test like I did with the Rift DK1 and DK2 but with the Index.
It seems to be focused around 1.2 meters. Did more tests than shown in the video, but checking afterwards this one seems to have been the one most in focus when locking it in.
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Valve responded and stated that the Index has a virtual focal length of approximately 6 feet.
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Huh, so my test is way off, even if I repeated it. That's interesting 🤔
Where did they respond, over email?
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I went through Steam support and asked the question. They responded with a steam message.
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Adding that to your original post would be nice, even with a screenshot for posterity, if you feel like it that is 😅
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I believe it is supposed to be 2m.
Sounds correct, I think the glasses I use inside the Index have 3m (10 feet) focal length and they work perfectly with the Index.