Distortion - Now I Understand

Well now I understand better why some users may be seeing some distortion in headsets like the Pimax Vision 8kX.

Lately, I have tried wearing +1.50 glasses to avoid some very short-term myopia after doing extensive ‘nearwork’. Unlike normal glasses correcting my vision, these cause substantial distortion, enough to actually give me a slight ‘VR nausea effect’ in ‘IRL’.

So it is plausible that any large lenses substantially ‘wrong’ for a person’s eyes will cause some distortion.

If you have contact lenses, try wearing them. If you can use large FOV prescription lenses, maybe try those. If you are comfortable shimming the Pimax lenses to change focus, maybe try that. If one day we can order prescription aspheric glass lenses for Pimax headsets, that might help a few more people.

1 Like

Yes - I bought the largest lenses for my prescription glasses possible for just my 8KX. They work well for me even though I have a 60.5 IPD. I can’t use any bi-focal types with VR for the same reason. I have a friend who wears contacts with his 8KX and it works well for him.

1 Like

Not sure what your are saying. Are you saying that people who have perfectly fine vision but are bothered with the pimax distortion should buy lenses to somehow correct the Pimax distortion? This makes no sense at all. It’s just simply a pimax lens problem
Most of the lens is fine but the outer 10-15 % just isn’t very good, causing distortion. No contact lens will fix that

2 Likes

People who are not slightly nearsighted may experience significant distortion due to the focal length of Pimax lenses. Using corrective lenses prescribed for use seeing objects ~4m distant may reduce distortion substantially.

2 Likes

My real peripheral vision is not very clear . . . . so I have to turn my head a bit in real life also . . .

2 Likes

But that would appear then as distortion away from the center where you’re focused on. So on the sides of the periphery. The problem that many experience with the pimax headset is that if you look through the edges of the lens, the image is distorted. It’s just a lens property.

Can you please elaborate on that? Is there some instructions on that? Actually i never noticed distortion on my original KS 8K, but now after going forth and back between 8KX and that, both with conmfort kit I wonder how I was able to overlook it. Plus, my leading eye is short sighted, not somuch of a deal IRL but in VR with clearly separated viewports it clearly is.

There are youtube videos showing how to carefully remove Pimax lenses with suction cups. IIRC, someone placed some shimming foam between the lenses and where they are mounted to change the focus a bit.

However, the ‘if you are comfortable’ part is a significant consideration. Any dust or misalignment will be very difficult to undo. At the very least, if you have two headsets, practice on the less expensive. headset.

It’s not really about clarity. Its about fish-bowling when you turn your head.

2 Likes

Well I guess I am lucky as I do not have that problem!

As someone who has been in the Astronomy world and Astrophotography world for a long time, I can tell you field curvature from a telescope or eyepiece takes several lenses (field flatteners) to remove the field curvature based on the focal length and whether it is for the eye or a flat imaging chip. The wider the imaging circle (or exit pupil) the more the curvature distortion shows up. I have eyepieces that cost more than the Pimax 5k plus that are multi element that color correct (fact the different wavelengths focus at different points through a lens) so multi element lenses or field correctors are needed to fix those issues. Anything can be improved, but if you are asking to have a 170 degree wide apparent FOV that is color corrected, and flat field corrected with good eye relief and a large exit pupil you will need to spend the money to do so. Single element Fresnel lenses can only do so much . . .

7 Likes

No doubt, i’m sure that’s why the x-tal costs way more.

What I don’t understand are people to whom the minor peripheral distortion for the price is a deal breaker.

I guess they want perfection ÷ FOV or nothing at all.

The recent Vive Pro announcement claims 120 fov. With the same form factor i’m guessing its either valve level marketing spin, or a curved screen allowing them to squeeze and extra 10 deg.

Either way in terms of impact i think maybe Pimax still is arguably better because i’d rather have 170 deg.

2 Likes

My only explanation is that the distortion they are experiencing is WAY worse than what I’ve experienced. The distortion isn’t even detectable when looking for it in some games for me. In some games I can detect it in the corners if I strain my eyes to focus on the corners of the display. Either way it is a complete non-issue for me during game play. Therefore, I imagine that those who complain about it are experiencing something far worse than what I get.

3 Likes

Headshape, comfort setup, and distance to lenses are key here. And the design of Pimax headsets make them far more sensitive to this than most headsets. For many people they are anything but plug and play.

I had no distortion problems with my 5k+ when using double thick foam, a top headstrap, and a counterweight.

But trying it with only the included thin foam was horrific. ‘Massive dynamic fishbowl swim’ is the best description I can give :smiley:

Even with the 8KX I’ve swapped out the Comfort Kit, and use 3rd party thick foam, top strap and counterweights to get it right for me.

1 Like

You also got to remember that when comparing the earliest versions of the 5k+ and the latest versions of the 8k-X, distortion wise they’re just world’s apart. Pimax has done a great job squeezing the most out of the current lens design and optimizing it for distortion.

That being said, it’s just another problem that needs to be dealt with. To me distortion right now is comparable to SDE on the 5k+. Most of the times I don’t even see it, but when I do, it can really break the immersion. In the end, VR is about 1 thing: how convincing is the VR world, how good is it at tricking your brain into thinking that the VR world is real. And distortion does play a role there, at least in my experience.

Interesting notion! Now I think of it, all fresnel lens headsets that are distortion free have stacked lens design. Even the StarVR, with wider FoV than the pimax, is distortion free but indeed has stacked lenses … And HTC is now switching to stacked lenses too. Pimax probably needs to look into that too

Flip side of that is that for 80% of people, Pimax headsets fit better than the others.

VR headsets seem worse off than any other wearable tech insofar as many people actually have defective eyesight outright needing correction.

1 Like

Did you ever wonder why those people don’t have any problems with the StarVR? Your point seems to be that people who see distortion have eye problems. That’s just such nonsense. Please stop pretending that Pimax’s lack of lens engineering knowledge is somehow the user’s fault. Pimax should just make better lenses, like StarVR’s for example.

2 Likes

This is so true,i didnt had any problems with the star vr one…They did something right with their design off the lenses

1 Like

Wow. I worried about the possibility of that statement being misconstrued, and I sincerely apologize for making the mistake of leaving any possibility of such implications.

No. My point was merely that VR headset technology may be more difficult than other ‘wearable’ technology.

4 Likes

Ok no worries @mirage335, I misunderstood you then.

1 Like

This is not Pimax related but I was having troubles seeing clearly in my right eye and two years ago I underwent LASIK eye laser surgery, partly so I didn’t have to use contact lenses in my VR headsets.

Turns out my right eye has developed some cilindrical focus issues recently and that’s the reason I couldn’t focus correctly in that eye haha