[DIY] The Big Fresnel Lens thread!

[Okta]

Im sure most of you have seen or tried your own fresnel lens setups in the past and know how great it can be. Since its another form of immersive gaming i think its relative and in some cases compatible to 3d stereo. I am going to get one again because im throwing the towel in at stereo for now because i have an 8800gt and no working options (unless a cheap vr920 comes my way).
For those who havent seen a fresnel setup first hand not only can it give you a MASSIVE screen but also the extra depth perception doesnt have a stereo effect but makes your eyes focus much further past the screen and thus this actually really look far off in the distance. This has to be seen to be believed but its very cool. The added bonus is it will work with all your games and have no driver issues


My old setup was with your typical 180x260 page magnifier on a 17inch crt with a cut out cardboard box for a body much like this -

http://www.tacticalneuronics.com/content/Fresnel.asp


It worked great but you had to put your nose against the lens to see 'inside' the virtual world so the immersion was awesome and fov maybe 140 degrees but very uncomfortable and a strain on the eyes.

On the whole suitable lenses are hard to find so im listing some sources here and please add any other sources you can find.


A popular easy setup these days is the f550 lens on a 19inch lcd from http://www.3dlens.com/shop/largefresnellens.php
This is slightly larger than a 19inch monitor and apparently is very clear and not distorted with a long focal length so you can sit it back further from the screen and have a comfortable setup.
This lens is also probably the best choice for the cool 3x19 TripleHead2Go setup. This is a cheap option to buy 3 19inch ebay lcd's and the matrox unit and some lenses mainly to hide the lcd frames-

http://home.comcast.net/~seekeating/r/th2go/

http://www.youtube.com/watch?v=QX4lGIuUvAc

http://www.youtube.com/watch?v=0yULvHspx8g



For those with a 24inch widescreen there is this one from frex but a bit pricey and unknown quality.

http://www.frex.com/gpshop/catalog/prod ... ucts_id=58


I also emailed this guy who sells large lenses said he will cut and frame lens to size on request for monitor purposes, not sure how good the quality is.

http://stores.ebay.com.au/greenpowerscience


Here are some tv screen magnifiers i found. I might get one of these simply because it is big and has an adjustable frame and will be future proof for bigger monitors. Unfortunalty is has a nasty blue tint that i have no idea why its there (anyone who has tried one can you comment please?)

http://cgi.ebay.com.au/ws/eBayISAPI.dll ... :IT&ih=003



So please discuss your setups and share any info or questions here.

[sharky]

ehm, maybe i didnt get it, but you see only the center of the screen? this is what i get from teh first pictures..

[Okta]

Thats the one like i had. The camera is too far back you need to pretty much put your nose against that one and then look around inside the box to see the whole screen but the result is huge.

A lot of the pictures seem blurred or distorted because its hard to get the perfect spot for the camera.

[Freke1]

I have 3 F330 and 3 CRT monitors. Haven't bought the TripleHead2Go yet though.
Sometimes I use one F330 with my CRT if I want a bigger screen (makes my 19" look like 25").
Bought mine from 3Dlens.com. Just fun and games I had to try it.

[Okta]

Have you managed to get the 3 setup and eliminate the borders nicely? The triplehead2go can be gotten for about $200 on ebay man how can you resist

[Freke1]

I bought it before Nvidia's Zalman only driver.
Now I don't know what to buy - so I just wait. Maybe a triple Zalman with Fresnel lenses if it work and I get rich
Also a fellow BF2 player borrowed one of the CRT's.

[Okta]

MyF550 from 3dlens arrived yesterday and after doing a bodgy mount onto my old cardboard box frame it fits ok.
It works very well and is a nice lens but i wish i could have gotten a bigger one because with my 19 lcd i have to keep my eyes no more than about 60cm from the lens or else i start to lose screen edges.

It would be great on a 17inch ,might start using my old crt again and get some shutter glasses, but then i need a 7900 as well

But as it is ive been playing Crysis and it absolutely rocks Should be nice once my (nasty cheapo) 5.1 usb headphones arrive.

Also HL2 was great with the kind dragon anaglyph.

Now, should i get a 28inch lcd and u huge custom cut lens or wait and see if stereo is making a comeback...

[LukePC1]

Are frasnel lenses compatible with any S-3D method, apart from shutters? I mean, all polarized light looses the polarization, so passive Polarized rigs are all out

HMD's might be nice with small ones, but they should have similar optics already build in. But maybe its possible to build 'glasses' and wear them with a hmd to increase FOV?

[Okta]

Anaglyph and shutter are ok but i have heard of problems with polarization so maybe someone with some experience can shed some light.
I think all hmd's use a lens of some type so its interesting that most users complain about the poor FOV. I do wonder if the FOV could be increased with further lenses.

[chrisdfw]

Anaglyph and shutter are ok but i have heard of problems with polarization so maybe someone with some experience can shed some light.
I think all hmd's use a lens of some type so its interesting that most users complain about the poor FOV. I do wonder if the FOV could be increased with further lenses.

I can confirm from trial and error that fresnel lenses mess up any polarization.

[flexy]

can you guys recommend for a widescreen 22" LCD?

I am new to this..but it seems very interesting.

[Okta]

The only large ones i know of are from 'greenpowerscience' ebay trader in the link. He dais he can cut to specific size but im not sure on the quality. I would get one at least a few inches bigger than your monitor so you can sit further back for comfort and in case you get a bigger monitor later.

[cybereality]

I had a similar setup a few years back. I found out about the fresnel lenses from some "build your own projector" PDF I found. I used a 17" CRT monitor and built this make-shift box around it to slide the lens in and about (similar to the link Okta posted). As a projector, it sucked. Technically it did work, I turned a 17"er into a 57"er but it was blurry as all hell. Plus, the picture was very dim so I had to literally duct-tape cardboard over my windows in order to see it (yeah, I'm hardcore like that!). However, I did notice how immersive the image looked when you stared right into it. Its pretty crazy.

With a fresnal and shutter-glasses on a small 17" monitor, it gave a pretty convincing sense of depth. Everything seems much bigger, like I was in a real space. Granted, the image was still very blurry (expect for right in the middle) and not very tolerant to head movement. Even so, it showed some promise. Its not the type of thing you will want to run 24/7 but its cheap enough that its worth checking out as a hobby project.

I've been thinking if maybe theres a way to mod some fresnels into the VR920 for increased FOV. I don't exactly want to take the unit apart, but maybe theres a way to make fresnal glasses that can be worn on the face instead? That would solve one issue (being that you need to be close to the lens for a focused image). Not sure how that would work with the existing optics in the HMD, though. Could be an interesting experiment. Maybe with one of these on a head-band:

http://www.3dlens.com/bookmarkmagnifier.htm

[Synexious]

The only large ones i know of are from 'greenpowerscience' ebay trader in the link. He dais he can cut to specific size but im not sure on the quality. I would get one at least a few inches bigger than your monitor so you can sit further back for comfort and in case you get a bigger monitor later.

I just bought a 27" Acer HN274H and am looking for a suitable fresnel. I thought it would be a good idea to have a slightly larger lens, and Okta seems to have confirmed this, but how would that effect a future triple setup? I guess with proper spacing everything will be fine, but I wonder if there would be any gaps in the image.

The greenpowerscience vendor page says custom lenses start at $300. I can get this Magnifying Aids (which seems to sell the exact same lenses as MaxiAids) lens for $67. Is the price disparity because of a difference in quality, or simply because custom orders are more expensive? It probably has the blue tint, but one reviewer said he didn't mind it. Another reviewer said it even worked well for desktop use, in fact, she said it made reading off her monitor more comfortable, which is contrary to what many have said about fresnels.

Information on fresnels is extremely hard to come by. I would really appreciate any assistance on finding the best fresnel for a 27" monitor (which will eventually become a 3DVS setup). I may just have to pay $67 for that TV magnifier and see if it works. I don't see any other buying options (all the sites I've found - which are all terribly designed - seem to be selling the same lenses, anyway).

[Tone]

Dunno if anyone is interested in this approach to a super wide FOV monitor based system. (Yes, there's fresnels involved.)

Look at the pix, then I'll explain:

Arno1.jpg

Head Mounted
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Arno3.jpg

Lenses viewed from the monitor side
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Arno2.jpg

Lenses from the viewer side
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Arno4.jpg

Optics and electronics (power supply not shown)
G4 frame is 11.5" wide and 6" high
______________________________________________

So... what we've got here is an optical system for a wide FOV (100 deg.) stereoscopic view of a 15" monitor. The monitor is placed about 8" in front of the bulgy side of the lenses. Sandwiched in the optics are: custom molded 2.75" dia. aspheric plastic lens (with nose cutout), press-on fresnel, polarizing sheet, 4"x4" LCD shutter, and a second polarizing sheet. There is also an electronics board and power supply to drive the shutters (more on that later.) All this, times two - one for each eye. The fresnels are used to achieve 100% overlap (otherwise it becomes painful to converge your eyes on a monitor that's 8" away.) The fresnels can be removed if you want to run at about 80% overlap and a correspondingly wider FOV, but your image generator must be able to handle this non-standard overlap.

The frame is made of several custom routed layers of G4 fiberglass. The routing was CNC milled to fit the lenses, shutters, and cable runs.

The electronics control board will drive the shutters anywhere from 30hz to 120hz. You just need to supply a TTL sync square wave. Alternatively, there's also an NTSC sync circuit which would allow field interlaced NTSC to control shutter sync. These were originally used with a 120hz 15" CRT monitor. Because of the polarizers, some LCD monitors may not work. In general if your LCD works with stock shutter glasses, it should work with this rig.

Don't know if anyone is interested. I have a bunch of these. Probably won't be super cheap. If there's interest, I can do a more detailed write-up on VRtifacts and put this system in the VRtifacts storefront.

[Synexious]

That looks elaborate. I don't understand it completely. These aren't glasses which can be worn freely, but instead must be fixed in place in front of the monitor? How large can the monitor be, and how does this compare to fullsize fresnels? This wouldn't work with multiple displays, right?

[Tone]

The optics are setup for a 15" monitor. Going larger wouldn't help...with 15" you get a huge stereoscopic field of view. Two monitors might be possible if you were to use more powerful press-on prisms and turn them 180 deg. so that your vision diverges outward instead on inward. Yes, this needs to be fixed about 8" from your monitor. You could do a boom arrangement for 6 dof.

Here's how these optics were originally used with a Viewsonic 15" CRT monitor. There's a black thermoformed bezel covering the optical mounting plate to hold the speakers.

Arno5.jpg

Arno6.jpg

Arno7.jpg

[Okta]

That is cool i had always considered building a very similar setup. As long as it is mounted so you can sit comfortably it would rock.

[cybereality]

Interesting rig.

[Synexious]

I understand now; this is a stationary "HMD." Why would a larger monitor not make a difference? Does this function differently from a regular fullsize monitor fresnel? Because with those, a 17" looks like a 24", and a 24" looks like a 31", or whatever, and so on. In other words, the screen is enlarged to a certain degree, but the larger the physical screen, the larger the magnified screen. You're saying that's not the case for these stationary glasses? What's a boom arrangement? Having the monitor on a swivel? That doesn't seem practical, but the lenses themselves are intriguing. Do you prefer this over a regular fresnel setup?

[Johnny-Mnemonic]

What's a boom arrangement?

Here is what Boom is:


Great device Tony!
Would be interesting to read an article about it on VRtifacts!