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View Full Version : An alternative to fresnel lenses (cheap!)



Lurch1962
02-24-2007, 09:51 PM
For $2 I just bought a pair of reading glasses from a "Dollar Store" that have a diopter rating of 3.5. That's a focal length of 285mm, or 11 inches.

With glasses on, I place my face within about this distance of my 19-inch flat screen monitor and...

I fry my brain! http://forums.ubi.com/images/smilies/784.gif

Seriously, though, aside from the nascent tumor I'm cultivating by doing this, I enjoy a nice and wide apparent field of view almost as large as that from the fresnel lens I've been using for the past year or so.

More benefits... I'm not as constrained in positioning because now I can move my gourd (noggin) around a bit more, and more importantly, the view is VERY MUCH sharper!

--Lurch--

Popey109
02-24-2007, 10:02 PM
Lets see,
Dot on forhead...check!
Head phones......check!
Glasses..........check!
Total geeeeek look....priceless! http://forums.ubi.com/images/smilies/25.gif

Lurch1962
02-24-2007, 10:13 PM
Har har har!

I forgot to mention one fairly important thing (to further increase the un-cool geek look)... get 'em with the biggest lenses possible. DO NOT settle for the cute little teensy things that more resemble tank slits! You need a big field of vision, and you don't want to have to glue the lenses to your corneas, do you?

--Lurch--

Popey109
02-24-2007, 11:18 PM
LOL! I was just funning with you Lurch1962 http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif
I could care less what I look like when I'm in a killing mood http://forums.ubi.com/images/smilies/784.gif

x6BL_Brando
02-25-2007, 04:18 AM
Lets see,
Dot on forhead...check!
Head phones......check!
Glasses..........check!
Total geeeeek look....priceless!

You better believe it. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif I'm quite used to hearing a sharp intake of breath when I stumble downstairs in my flying kit and confront the postman or the dispatcher. I love watching people wrestling with incredulity & politeness as they look at my stubbly chin, huge specs and an old golf visor with a large 'dot' stuck on a piece of plastic tubing wedged on the brim. Works a treat with strange evangelist door-steppers too. Try getting them involved in discussing the comparative rates-of-fire between Russian & German aircraft armament circa 1943 - and keep scanning the sky behind their heads for enemy aircraft.
"Bogeys @ your high six, I say, turn 180 and maintain altitude. Out." Works like a charm http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

B.

major_setback
02-25-2007, 04:39 AM
Latest multi-reflector hat from Natural Point:

http://data1.blog.de/blog/h/horse1/img/lucille-ball.jpg

John_Pimlott
02-25-2007, 04:48 AM
This calls for photographic evidence.
http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

PBNA-Boosher
02-25-2007, 09:27 AM
Only thing I'm worried about:

Lenses that close to the eye, though. Even if you don't need them, Aren't you damaging your eyes even more than you would be just looking at the screen by wearing them, especially if you're leaning close in to the screen?

dbircsak
02-25-2007, 12:02 PM
I don't think you can fry your eyes on a flat screen monitor... they don't put out radiation like the old monitors did.

Doolittle

triggerhappyfin
02-25-2007, 02:02 PM
http://img.photobucket.com/albums/v257/Triggerhappyfin/glos.jpg

Whats with them eyes?

ZappaTime
02-25-2007, 04:55 PM
Dedication to immersion - http://forums.ubi.com/images/smilies/sadeyes.gif how funny must you look - photo please

XyZspineZyX
02-25-2007, 05:50 PM
Originally posted by John_Pimlott:
This calls for photographic evidence.
http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

http://www.mattiouz.com/images/bubbles.jpg

Lurch1962
02-25-2007, 08:53 PM
Boosher,

Your eyes won't be hurt at all. The idea is to find the point where the screen's in focus comfortably. The positive lenses do the work of focusing on the close-in screen, and all you have to do is move back and forth to find a comfy "sweet spot."

I will admit that one has to converge the eyes to a fair degree, but this shouldn't cause any discomfort. After all, you do it all the time whenever you examine something within a foot of your face.

Unless you're well on in age and your own lenses have hardened (loss of accommodation), you'll naturally do a little re-focusing as your eye-to-screen separation varies.

A more comfortable alternative is to find reading glasses with a smaller diopter rating, say, 2.5. The longer focal length means you can hang back farther from the screen, and the comfort zone is wider.

A final caveat... if you have really bad astigmatism the reading glasses will not work so well by themselves. Of course, you could remove the earpieces from the reading glass lenses and attach the lens-holding part to your prescription goggles.

And guys, trust me. You don't need to see a pic of moi! http://forums.ubi.com/images/smilies/53.gif

--Lurch--

BillyTheKid_22
02-26-2007, 12:59 AM
hahahahaha!

Max.Power
02-26-2007, 02:26 AM
I would consult an optometrist before doing this for any length of time.

STENKA_69.GIAP
02-26-2007, 10:28 AM
Last year I got my optician to make me a set of specs just for working the screen - set to about 20". Hated the damn things... needed to lift them to see keyboard or grab a beer....

Made it more critical exactly what distance head was from screen.

Threw them in the corner and fitted a Freznel lens. Now the point of the freznel screen is that your eyes focus out to infinity no matter how close you are to the screen. It reduces eye strain as well as giving a sense of depth.

The two are not the same thing. Anyway the screen only cost 45 Euros - not a big deal. personaly I wouldn't take $2 risks with what's left of my sight...

AVGWarhawk
02-26-2007, 11:50 AM
Is this something like the Optigrab from the Jerk