5/8k NON - Fresnell lenses

Hey

I can’t deal with fresnel lenses. I even moded my Vive using GearVR lenses to be clear only and given all the extra degrees fresnel was meant to give me I see absolutely 0 differences between them…

I wonder if there is a way to buy non-fresnel lenses for pimax headset if I ever to get one ?

TIA

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Fresnel lenses have some advantages for VR applications and Pimax spent hundreds of thousands of dollars designing their current lenses. I think it’s unlikely that you would be able to fit existing conventional lenses (anything you could buy off-the-shelf) for the Pimax.

Fwiw, the Pimax lenses are pretty good (but I do occasionally see faint Fresnel rings, when there are bright objects on a black background).

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I agree with @neal_white_iii. The lenses seem to be much better than the ones used on the Vive for example.

You should try a headset if someone has one locally and see for Yourself… :face_with_monocle:

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GearVR lenses are far better in terms of clarity. All frensel lenses including my Pimax give this feel like observing world through glasses with thin foil on it. Period. PPL shold try it before saying Pimax lenses are great.They are good enough but when your try gearvr lens mod with Vive panel you will see huge diference.

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I tried some gearvr lens in my pimax , super clear and brighter picture but would need a bespoke holder of some kind and you loose the wide FOV

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Hey

Thanks for info.

I’m not sure… will try to get off amazon & return it if its odd but I’d rather avoid that.

I don’t think fresnell lens will be good. I wish they would just go with normal glass and sacrifice 10-20 degrees in favour of much clear look. I have Pimax4k(now damaged since it broke after falling off 40cm chair… sigh), but when I compared p4k and Vive I was like. WOW this looks amazing. And I stopped using Vive, then Pimax broke and I went back to vive crying, after a while I’ve moded vive with gearVR lens and oh wow, vive become amazing. I can see pimax5k/8k will have the same issues as any other Fresnell based lens.

I still cant believe Pimax is not clear lens, this is the reason I did not buy the headset in 1st place.

Perhaps a moding company will release lenses for 40-60£ for 5k made out of glass.

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I agree the Fresnel lens is not optimal for vr

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Those glass lenses would likely be quite heavy and would likely be too thick to fit the current headset. Also, a pair of appropriate custom lenses would probably be more like $400-600+ perhaps a lot more (look at the prices of camera or telescope lenses of similar size).

I think I will have a proper go with some gearvr lens , cobble together an adapter of some kind ,

Hmm not sure about the weight… I kinda remember people said that about gen1 Vive that they had to be plastic fresnell due to “weight/view/fov/etc/etc”, and yet when you drop in gearVR one there is almost no difference. (except for obvious clarity and much larger focus spot)

What weight we talking about here, 5 extra grams?

I’m not sure if they need to be glass, whatever gearvr ones are made out of should work.

On another side, I wonder if we can take the Pimax fresnell lens and just sand paper away the fresnell part? Maybe there is a way to polish it out to hell and get nice clear lens?

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One possible problem with putting a non fresnel lens into the pimax is that there is a glass protective panel beneath the current lens which would mean that any replacement lens would have to protrude a bit , maybe much thicker face mask etc could work.
Sanding a fresnel does not make a regular lens with similar magnification

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I do not think that fresnel lens is not optimal for vr, but Pimax lenses should be imoroved.

They can not fully utilize their panels, making 25% of each panel useless.

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The top poster in the comments of this thread offered to print prototype lenses if given the lens geometry if anyone’s game to pop their lenses out, record geometry and send him a PM.

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In the best case you will lose 170-130 =40 degree horizontal, and have a Valve Index type of FOV. This is a reoccurring question here and like said by @neal_white_iii no easy or cheap solution here!

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Not true, a cheap aspheric lens can be made out of an optic plastic from third party sources

In large volume yes but it’s not true for only one unit ( a quality plastic lens)

Seriously here if it was so cheap and easy why HTC , Valve, Samsung, Oculus, Pimax use them and why those lens are not in every camera on the market.

Fresnel lens have clear advantages for power and compactness vs normal spherical non Fresnel, for a standard lens the higher the power of the lens is the more tick it will be and the more chance bubble air will be trapper in the lens. VR headset use very powerful lens of 15 to 25 diopters so this increase even more the price

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Because custom aspherical lenses are expensive to design, but if you have a design the manufacturing is cheaper if you’re using a plastic alternative instead of glass.

GearVR lenses are not expensive. The whole product cost 200 with room for profit, the lenses couldn’t have cost more than 50, and they are plastic aspheric lenses

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Look at the given chart… we can have gear VR lens for cheap yes because someone ( Samsung) paid for the development. An then you lose some FOV and then you must redesign the distortion profile and I’m even not talking about the distortion of those single lens

Not impossible surely but the goal of the pimax is to have a large FOV, so unless you go for a full ultra sharp less large sweet spot lens with no chromatic or barrel distortion I don’t see the point of modding the pimax headsets, use a Samsung Odyssey+ instead you will gain Oled panel in the process for a 110 FOV…

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That will produce a nice flat piece of plastic with no significant optical properties. A Fresnel lens is essentially a conventional lens with the “inside” material removed (only keeping the lens surface). Once you’ve removed the outside too, you don’t have anything useful.

image
From: Fresnel lens - Wikipedia

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What they need is a hybrid design where you have an aspherical lens in the center, and then fresnel in the outer portion.

I don’t think it’s physically possible, but what I have heard is that the clarity on the current design is best at normal FOV, and that’s because with fresnel lenses (all optics really) it gets harder to have clarity the higher FOV goes.

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