here you go
here you go
lens-manufacturer.com
I used them (previously called optolife)
cheap fresnel lenses and they pack well, but two of my fresnels ordered from them had each a small scratch but were not really visible.
DON'T use them to buy triplets or any projection lenses, my one was so crappy I couldn't get anything into focus
here you go
lens-manufacturer.com
I used them (previously called optolife)
cheap fresnel lenses and they pack well, but two of my fresnels ordered from them had each a small scratch but were not really visible.
DON'T use them to buy triplets or any projection lenses, my one was so crappy I couldn't get anything into focus
there were a few US-based companies like lumenlab, Australian-based company diyprojectors.com I think, but most of them no longer sell stuff
you can keep an eye out for surplusshed.com as they are US-based and have a lot of lenses and optics and have had fresnel lenses for sale in the past.
What is the size of your LCD as you may be able to use overhead lenses
you can keep an eye out for surplusshed.com as they are US-based and have a lot of lenses and optics and have had fresnel lenses for sale in the past.
What is the size of your LCD as you may be able to use overhead lenses
Overhead projectors have 2 fresnel lenses glued at the edges together, usually a 220mm one for the collimator (facing the lamp) and a 330mm one for the field fresnel (facing the lens)
Is your 15" LCD 4:3 aspect ratio or is it 16:9 or 16:10?
If it's 16:9 or 16:10 you won't be able to use an OHP fresnel as it won't cover it, but if cut screen edges don't bother you then that's fine. If it's 4:3 you might get away with it.
Also when using an OHP lens you need to match your projection lens to the 330mm field fresnel in the OHP.
There's plenty of OHP fresnel lenses for sale on ebay in the US, just look for fresnel lenses and you should get a few results.
Is your 15" LCD 4:3 aspect ratio or is it 16:9 or 16:10?
If it's 16:9 or 16:10 you won't be able to use an OHP fresnel as it won't cover it, but if cut screen edges don't bother you then that's fine. If it's 4:3 you might get away with it.
Also when using an OHP lens you need to match your projection lens to the 330mm field fresnel in the OHP.
There's plenty of OHP fresnel lenses for sale on ebay in the US, just look for fresnel lenses and you should get a few results.
abradatanu you are a treasure and i thank you very much. i actually just got hold on a OHprojector from craigslist.
But how do i seperate the two lens? You say they are glued, but god they are so well glued. i am trying to split them up but start breaking apart slowly so i stopped.
Suggestions?
But how do i seperate the two lens? You say they are glued, but god they are so well glued. i am trying to split them up but start breaking apart slowly so i stopped.
Suggestions?
I never actually separated an OHP lens myself but what you could try is using a hacksaw and slowly cut the glued part away and that would free the lenses. The only problem with this would be that you would get a lot of dust in the fresnel lenses rings and trust me when I say they are HARD to get out.
Another option would be to find some glue solvent that would soften the glue just enough for you to pry open the lenses but this would be difficult as you can't know what glue they used and what solvent to use. And on the other side it might damage the lenses, although they're made of acrylic. I'm not sure about this.
The third and most easy solution would be not to separate them. Unless you're doing a split projector there's really no need for you to separate the two lenses as you can cut them to size or just use them like that.
In my opinion a split design is a really bad idea as you are effectively placing a sheet of plastic with rings on it in front of your LCD which severely degrades the quality of the projected image. Sure you can do a bit of keystone with a split design but is it worth it? NO
Another option would be to find some glue solvent that would soften the glue just enough for you to pry open the lenses but this would be difficult as you can't know what glue they used and what solvent to use. And on the other side it might damage the lenses, although they're made of acrylic. I'm not sure about this.
The third and most easy solution would be not to separate them. Unless you're doing a split projector there's really no need for you to separate the two lenses as you can cut them to size or just use them like that.
In my opinion a split design is a really bad idea as you are effectively placing a sheet of plastic with rings on it in front of your LCD which severely degrades the quality of the projected image. Sure you can do a bit of keystone with a split design but is it worth it? NO
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