Newbie question: effective focusing distance

I almost posted this in the “distortion” thread because there are obviously knowledgeable people on it, but on reflection it wasn’t on-topic.

I’ve pre-ordered an 8KX. I’m pretty much a newcomer to VR in that I’ve tried a few devices in the past but have not been sufficiently satisfied with the quality to buy one, until I heard about this product.

A complicating factor for me is that as a result of surgery for early-onset cataracts I have artificial intra-ocular lenses inserted in my eyes. My left and right eyes are set to different distances. I don’t believe this will be a show-stopper for me, but it might require a special pair of glasses to set my eyes to the same distance. I already have such a pair for computer work, which sets both eyes to about 60cm.

So apologies if this information is available somewhere on the Pimax site, but if it is I have been unable to find it. My questions are:

  1. What is the effective focusing distance using an 8KX headset?
  2. Is it adjustable, and if so what is the range of effective focusing distances?
  3. Is the focusing distance adjustable for each eye independently?

Thanks in advance.

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1/ I don’t think there is an official number, but I think it’s around 1 - 1.5 meters. Also, personally, I think it’s different across the width of the lens. I think it’s closer the further towards the outer edge and maybe the bottom. I saw someone comment recently that this is inevitable with the angled screens, but I don’t know for sure.
2/ No. Edit : Well, you can use a thicker or thinner face foam, that makes some difference.
3/ No :frowning:

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I think @risa2000 had a questimation about the focusing distance.

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a Pimax person once commented that it was “1 to 2 meters”, people have attempted to measure it and come up with a figure of 1.2 meters, I think thats about the best answer we are going to get

you can probably use your glasses in the headset

but no, there’s no adjustment for it on pimax headsets

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OK, thanks all.

When my 8KX eventually arrives I will report results.

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What is your uncorrected eyesight? If just a little worse than 20/20, it may not be worth correcting. Also, some users have removed the lenses with suction cups, shimmed the edges, then put them back, changing the focus slightly.

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This is a great question. I and many people who wear glasses need to know the answer. It’s unfortunate that Pimax did not include in its headset the ability to adjust the focus. I also have a pair of glasses specifically for computer sessions. Its focusing distance is about 1 meter, maybe a little less, so I’m hoping I’m all set.

All of the mechanical complexity of the Pimax headset ultimately probably comes from the IPD mechanical adjuster. I am not sure adjustable focus is something they could do.

It really isn’t that complicated. However, it would require enlarging the headset slightly, and it would cost more to manufacture. I’d like to have adjustable focus, but in the end I’m not willing to wait for all that it would take to incorporate such a thing. With further consideration… mechanical complexity isn’t a problem, but adjustable focus would wreak havoc with field of view issues.

I don’t see how it isn’t that complicated. Optical alignment of the 8kX probably has a tolerance of micrometers at most, not tens of micrometers. Mechanical slides are rarely that accurate over the short distance the panels or lenses would need to slide forward/back. Even leaving out issue of compactness, the lenses would be more likely to tilt than move directly forward/back.

In lab optical mounts, and telescopes, the usual means of addressing this six-axis alignment problem is with very expensive mounts using adjustment screws, or very bulky flat linear stages. Neither are good options for the 8kX. People would be tinkering with these things all day.

All of which does nothing for people with astigmatism.

For all that complexity, if you want anything from Pimax for this specifically, you should be asking for a shim kit. Could take all of five minutes to install for specific diopters. Could easily be much better and more convenient than yet another set of multiple linear slides.

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Good point. Perhaps you could suggest it to them.

Or if it was really worth doing, I could just design and make the kit myself. I have 3D printers after all.

If…

Convince me, or do it yourself.

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Well I don’t have a 3D printer. With that and your idea, it sounds like you may have the beginnings of a budding business in your lap. Convinced yet?

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Or a laser cutter, which might be the right tool. But yeah, that one never gets old. Somehow more of these machines didn’t become less finicky in the last few years.

I’ll put this in my queue after the USBC ‘dumb’ power/passthrough hub.

For context, I had cataract surgery (for a condition that is not the same as normal age-related cataracts) in which my natural but defective lenses were removed and replaced with artificial intraocular lenses. My eyesight is dramatically better than before the surgery, but the artificial lenses have one drawback - being rigid they cannot distort to change focus the way that a natural lens does. There are various options available to cope with this, but my surgeon recommended lenses of different focal differences in each eye.

Uncorrected, post-surgery my right eye is sharp from about 5 metres to infinity. My left eye is sharp from about 1 to 4 metres. That sounds as if it would be rather disconcerting, but the brain is an extraordinary thing, because it sorts all that out. It combines the detail information from whichever eye is sharper for the object you are looking at with the colour and depth information from both eyes. The result is clear binocular vision from 1 metre to infinity without glasses.

Most of the time I wear bifocal glasses that have 1.5 magnification at the bottom and zero magnification at the top. This gives me an effective range of about 10cm-infinity. I could have gone with no glasses at all and just put on reading glasses as needed, but I’ve worn glasses all my life and it seemed easier than popping reading glasses on and off all the time.

For extended periods of screen use I have a pair of glasses which set both eyes to about 60cm and it is these that I intend to use with the 8KX. If it turns out that I need a pair set to a slightly longer distance then I’ll get some made.

I used to have quite bad astigmatism too but the artificial intraocular lenses fixed that.

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Ok. Very likely you will not get much benefit from any corrective lenses or other adjustments in the 8kX.
At those ranges, both eyes may be adequately in focus.

However, if the right eye is blurry for you, due to the focal distance being a bit close, you may be able to shim the lens, adjusting the focus closer to the infinity the lens in that eye is set for.

IIRC, there is a youtube video showing how to do this, but I can’t find it.

If it’s any help, I wear 3 different pairs of glasses depending on what I’m doing; I didn’t want varifocals. I have reading, computer and distance. Sim racing on screen, I use the computer glasses which range from about 0.5 - 1M. However, putting on the 8K I have to switch to my distance glasses.

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OK, thanks - that helps me visualise (as it were!) what is going on. Will report back when the time comes.

I think you might want to get some advice on whether the VR is going to give you any adverse effects. You could use prescription lenses from VRmust to correct your vision, but your brain is used to one eye being long sighted, the other short. So correcting both eyes with VR lens inserts might actually be counter productive (or give you eye strain, or something). Definitely worth a quick call with your optometrist or eye surgeon.

Fair point. I sort of already had that discussion with my eye surgeon, when I decided to get glasses for computer use set to the same distance. Her advice was (a) wait for at least six months after the surgery, to give the neural re-wiring time to happen, and (b) don’t use the glasses for more than a few hours a day. In the event I waited about ten months before getting them.

I find that using the glasses for more than a few hours does lead to some discomfort, so I have that helpful indicator about when to stop, and I guess that will be the same using VR. But I’ve had the glasses for about six months now, with no appreciable effect on the illusion of sharpness over the full range of focal distances when not using them. For “normal” computer use, such as reading and posting on this forum, I use my uncorrected vision. In fact I would estimate that the ratio of time I spend wearing the glasses is around 1:20 of waking hours, or less.

But I’ll definitely keep an eye (!) on it.

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