Projection Surface / Screen

[RJK_]

I wonder if someone can explain how far the projection on a HMD is away from the eye compared to a real world object. This seems a bit weird to me because in VR i am looking at a surface, not an object. I am not shure how the eye follows (in distance) objects in VR. Meaning , if an object moves away from the eye, how does the eye handle that while the object does not move physically into Z-space as it would in reality.

Background: I am having a serious focus problem beetween the left and right eye, now next time i go to the optician for some new glasses, i wonder which “distance from the eye” will be the best one for VR.

I guess an everage optician will not know much about “VR”.

[Ralf]

I’m not 100% sure whether I understand the question, but the stereoscopic focus (convergence) plane is typically set to infinity in VR, meaning left and right image match in the background and are farthest apart close to the camera. vorpX always does that in FullVR mode, in immersive screen/cinema mode you can change it, but as the message suggests that appears when you do so, that should be done extremely carefully, if at all.

If you have trouble focusing foreground objects, you have set the 3D-Strength too high.

Apart fom that artificial stereoscopy in general is somewhat odd for your brain since it doesn’t fully emulate what happens in reality, which is one of the reasons why some people consider stereoscopy generally uncomfortable. Most importantly accommodation (for thr sake of simplicity imagine it as the real world counterpart of a depth of field effect) doesn’t work as your brain expects.

I don’t think I’m able to fully explain that well enough in a few sentences, I’m not really a great teacher. If you want to learn more: the Wikipedia articles about stereoscopy and depth perception are good starting points.

[RJK_]

Thanks for your kind information and the provided links, interesting to read.
Let me try to explain my personal problem in another way.
In real world my eyes focus matches at about 1m. One eye sees sharp in distance, the other one near.(getting worse over the time) Meaning i have clear and sharp view at ~1m. In VR i cant really meet the range where both eyes see clear. Only over a certain amount of time, depending on how much i sat in front of the PC. Now, when going to the optician for new glasses, they will ask me for the distance in which i would like to see clear with both eys. (they did the last time where i bought two different glasses, one for far, one for near)
I beleive HMD lenses create a range where an image can be vieved sharply, but that was actually my question, what would i tell the optician ? 1m, 2m ? In therory there should be a range where HMD lenses produce best focus for the eye. This is the value (“distance”) i am trying to find out in order to optimize my seeing.

[Ralf]

You would have to ask yours headset’s manufacturer at which distance the focal point of their lenses lies. I‘m not really the right person to answer that question. I‘m pretty sure that it‘s typically within the range you mention, i.e. something between one and two meters, but I can‘t really say anything more precise.

If your eye sight isn‘t good enough anymore to get a sharp image at that distance, you should be able to counteract that with mild prescription lenses just like the ones you probably use for reading, just less strong. Before buying new ones it’s worth to check whether you maybe still have an older, less strong, pair stored away somewhere that happens to work.

However, if you want/need precise information, your headset manufacturer is the only one who can answer your question.

[RJK_]

Thanks Ralf, good idea, gonna ask HTC, in case i get an answer ill report back here. Others may be interested in that information as well.

[slydog43]

I thought that Oculus at least settled on a focus point of 2 Meters. Hopefully in the future we can get a variable focus HMD like what was demoed at OC6 (half-dome), but only time will tell as that will add lots of moving parts and such cost.

[RJK_]

Dante from “the Vive Team” wrote:

(Translated)
Please forgive, but we cannot help you with this question.

[Ralf]

If you don’t need anything more special than typical reading glasses, there is a relatively easy way to solve your problem without knowing the exact lens focus distance: to figure out how strong the glasses need to be for each eye you would just have to buy a bunch of cheap ones from the supermarket/internet roughly within the range of diopters you suspect should fit. That way you could easily try yourself what works best for each eye and then let your optician make the actual pair based on that information.

Any larger supermarket should have cheap reading glasses in .25 diopters increments. Provided your eyes don’t require anything more special a handful of them within the suspected range should be enough to figure out what works.

BTW: If you don’t want to wear glasses in VR, you can also buy prescription lens inserts for all major headsets online. Personally I use inserts from vroptician.com for all headsets and am quite happy with them.

[RJK_]

I exactly did that and i came to the same conclusion. Some supermarket glasses tend to enlarge the image to a certain degree fore some reason though. It appears the regular glasses i got from the optician dont.

My brother ordered a pair of inserts too ( around 50E ) but hasnt reported back yet. I ll probably get some as well soon i get to know my current values.

[Author]

Posts