Cockpit builders or Condor pilots looking for a more immersive virtual reality experience may be interested in this.

I just recieved my #F550 fresnel lens from the 3dLens Co. in China.
It measures 320 X 400mm, about the same size as the panel case of the monitor.

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

It took only 5 days to arrive. I was following the instructions and recommendations from this site:

http://www.rickleephoto.com/rlcoll.htm

Particularly the recommendation for this lens in the September 2005 update section from David Grigg further down that page.

A picture tells a thousand words...so see below.
The photo shows half of the lens being held 200mm in front of my 19" Flat panel monitor. I now have a wopping 28" Diagonal virtual monitor, once I have built a box to hold the lens in front of the screen. Read the article above to see why the Fresnel lens is different than just using reading glasses. Now when I look at the mountains they truly appear in the far distance and the even close up mountains look very 3D. Its a breathtaking view.

This high resolution lens with very fine almost hard to see grooves was produced recently for the Do It Yourself projector community who are building high definition LCD projectors by using cheap 17" LCD monitor as the source of parts for the projection panel ( with the back light removed).

Let me say briefly * the quality of the image is stunning * there are no artifacts from poor lens quality. You could easily leave the lens on all the time. The other thing that has amazed is the great range of distance you can view from. Either with your nose up to the lens or at a distance of 600mm the picture remains sharp and in good focus with no eyestrain. And the increase of viewing angle is amazing , you feel you are sitting in the glider.

Have fun !

Mark

Wow, that really does look pretty good. I might have to try one of those. I was looking them up a while back on ebay, and it looks worth a try.

So it doesnt distort the image in anyway either then?

I have track IR now, so is it still possible to use it with track IR? I suppose if I place the device above the lens it should be ok?

Thanks for any responses.

The curved sides of the image in the photo is due to the wide angle lens setting on my digital camera. In reality the distortion is almost non existant.

The grooves in the plastic that make the lens are so fine they are barely visible at a glance and much finer than the grooves in an LP record.

I've played around a bit more and I agree with David Grigg that 9" spacing giving a 30" diagonal gives an even better image . I'm going to make ap a box to mount the lens tomorrow and will post results.

I also have a Track IR3. The sensor will have to be mounted on a short wooden post and pointed down a little, so that the reflected beam can clear the lens. Not a problem I don't think.

This is an awesomly cheap mod for flight simming that gives great results.
For those who didn't get far enough on the web page I cited in the last post , this was David Griggs report...

"UPDATE September 2005:
I just got this feedback from David Grigg:

Rick,

I found you website (totally by accident) and, as an avid flight simmer, had to try out the fresnel lens setup. I checked all around, studied up on the differences in fresnel lenses and finally decided on the F550 lens from 3Dlens.com. I would HIGHLY recommend this lens and this company.

It is amazing! This lens is just lightly larger than my 19" monitor screen and is very high resolution with its 0.2mm grove pitch. After some experimentation, I settled on a box depth of 9". The result was effectively a 30" monitor with incredible depth perception and virtually no distortion or loss of resolution.

I don't know how I ever survived without a fresnel lens before. I've been turning all my flight sim buddies on to your site and to the Fresnel lens.

Thanks for taking the time to put up this site. David Grigg. "

Mark

Looks really interesting.
Lets see some movies and pictures.

Anyone in DK that wants to buy "volume"

/Raven

Wow, that looks great,
few questions:
1. Is that box delivered with the lens? If not, how handable is that lens when mounting it on the box?
2. Mark is describing a ~50% increase of view, while Rick's picture shows much more increasement...
3. The term Groove pitch doesn't mean anything to me, what should it mean to me?
4. Does the focal length 550mm, mean that The lens has to be at least 550mm from my screen and from my eyes?

My brother wants one for his birthday in May, so I think I might buy one now and check it out. Any ideas of sharing postage of a few to Europe then distributing them from there?


As far as I know that is the distance between the concentric lenses. The smaller these are, the better the image looks otherwise you can see many concentric rings when looking through.

Just found another link too - more things to do with fresnel lenses

http://www-personal.umich.edu/~bclee/lens.html

Makes me slightly concerned about the effects it has on your eyes though

I ordered a F550, will let you know how it goes. £28 is a hell of a lot cheaper then I've ever seen a Frensel lense for, I hope the usual maxim of "if it looks too good to be true, it normally is" doesn't hold up here.

My dad will bring an old Overhead projector from his work...

[quote="TimKuijpers"]Wow, that looks great,
few questions:

1. Is that box delivered with the lens? If not, how handable is that lens when mounting it on the box?

No you will have to make a box.

2. Mark is describing a ~50% increase of view, while Rick's picture shows much more increasement...

Ricks diagram is not optically accurate although the graghical principle is right. The increase in monitor size depend on how far you hold your eyes from the lens. At 250mm I get closer to effectively a 40" size monitor.

3. The term Groove pitch doesn't mean anything to me, what should it mean to me?

The grooves are like the fine tracks in a Vinyl record but finer.

4. Does the focal length 550mm, mean that The lens has to be at least 550mm from my screen and from my eyes?

Yes that is the focal length, but 225 mm lens to screen distance is about right and viewing distance from the lens is best at 250 to 450 depending on how large a screen you want to see.

Mark

The 2 Fresnel lenses in overhead projectors used as light condensing lenses, typically have focal length of 225 and 300mm which will be too short for a large monitor, as the image will appear distorted. The spiral groove pattern is much coarser too, which will give you more undesirable reflections. Such a lens may however give you the general idea.

Mark

ok

just thinking right now:
What will happen if I place 2 lenses instead of 1..
(Big, bigger, biggest... )

Adding two lenses the same, halves the effective focal length of the system. Typical Fresnel lenses in an overhead projector have a 330 and 220 mm focus lens glued together.

BTW It looks like you can pay 395 Euro for similar if you want to

http://www.simkits.com/product.php?prodid=304

Reading Rick Lees original website , he was getting good results with a 275mm focus lens used on a 17" CRT ( 15.7" actual diagonal)

3Dlens also make a 330 mm focus in the large high resolution model ( # F330 ) This lens may be much better for 17" and under monitors.

Anyone interested in making themselves a Fresnel box I stress... * only buy the #F550 lens if you have a 19" LCD or CRT **** My results apply to this setup****.

If unsure why not buy both lengths and experiment. The 550 and 330 lenses are designed to work as a light condensing system for building high quality 1024 X 1280 data projector. All you need is a cheap projecting lens , a 400w Halide lamp and fan and a cheap 17" LCD panel to strip apart and you can build a high rez projector That would also be a great project for a gliding simulator.

Mark

It arrived today, well wrapped up and in one piece.

First impressions - Very nice. I didn't quite understand how it would replicate a 3d type display, but it does. The depth of the view is quite impressive, along with the increase in view dimensions.
All in all I can't think of a better value for money improvement you could make, short of buying a huge monitor.
The tiny grooves are visible, but you focus a lot further than the lens so I don't really register them that much at all.

Absolutely knackered after a long day at work so I'll do another review sometime later.

Texasuk

Great to hear that you got your lens and you are impressed with the results! Certainly cheaper than a 30" display and the depth effect is far better than just a big display. What a bargain.

I mounted mine on a 9" deep plywood box, but wasn't happy. Reflections from the monitor on the inside of the box ( even though it was painted flat black), gave me the impression always of looking at the monitor down a tunnel.

I've bought some light aluminium channel and I'm making a simple hanging bracket that slides onto the monitor and lets the lens hang in front like clothes on a clothes line. Monitor face must be vertical but I think that is necessary for a good virtual reality effect anyhow. Will post pictures as soon as its finished.

Mark