I just found that lcd while seaching on yahoo, i thought you guys might interested. I don't need it, I'm using the sony psone lcd screen for my projector, i want mine small, here's a picture of it. I'm using the Figinon lense from surplusshed. I had to build a stand for it, so it could be close to screen.
Attachments
Wwwwoooohhhaaaaaaaaaaaaaaaaaaaaa
the eyeglass thing works!!!!!!!!!!!!!!!!!!!!!!!!!!!
i've recieved my eyeglass today and first tests show that the picture is smaller; but the final test still comes, when i got my second projector finished...
i hadn't have the final distance but from the test it shows the picture is smaller and crystal clear and sharp... i will post pictures with the differences as soon as i have finsihed it...
@prjctr_builder;
if the lense from surplusshed doesn't work, the eyeglass thing is still a solution; mine cost me 11,50$ and in addition with my ohp lense i got the perfect picture from 7.78ft distance betwen screen and optic
just take a look at the top of the site; there i told u what eyeglass you will need to buy, but it is not for farsightly but short-sighted people as i learned ;-)...
slize
the eyeglass thing works!!!!!!!!!!!!!!!!!!!!!!!!!!!
i've recieved my eyeglass today and first tests show that the picture is smaller; but the final test still comes, when i got my second projector finished...
i hadn't have the final distance but from the test it shows the picture is smaller and crystal clear and sharp... i will post pictures with the differences as soon as i have finsihed it...
@prjctr_builder;
if the lense from surplusshed doesn't work, the eyeglass thing is still a solution; mine cost me 11,50$ and in addition with my ohp lense i got the perfect picture from 7.78ft distance betwen screen and optic
just take a look at the top of the site; there i told u what eyeglass you will need to buy, but it is not for farsightly but short-sighted people as i learned ;-)...
slize
it is an eyeglass with -0,75 dioptrin for short-sighted people, 65 mm in diameter in my case...
hello?
nobody is interested in my solution for the focal length problem? with that you can position your projector at nearly every distance from the screen. and you always have the perfect (sized) picture...
nobody is interested in my solution for the focal length problem? with that you can position your projector at nearly every distance from the screen. and you always have the perfect (sized) picture...
lens solution
Slize:
How bout some screen shots?
How big of a diameter lens is it?
It's a big breakthru if it works!!!!!!
Slize:
How bout some screen shots?
How big of a diameter lens is it?
It's a big breakthru if it works!!!!!!
Re: hello?
I'm interested. Can you explain where you are positioning your new lens?
slize said:
I'm interested. Can you explain where you are positioning your new lens?
please read the pages 106-107 there the idea is explained; but here is a short summary:
i am using a 3 lense ohp optic. the problem is the focal length is too short, that means the picture is too big at a distance of 8,75 ft to the screen...
the idea is to take a lense from eyeglasses at a certain dioptrin in additon to the ohp optic; i explained how to calculate that dioptrien number a few posts ago...
and used the program from the site prjctr_builder discovered...
the default setup is to put the lense right in front of the ohp optic, and by increasing and decreasing the distance it works like a zoom, because when there is room between the ohp lense and the eyeglass the focal length decreases and that means the picture goes wider... i am talking about max 0.8 inches between that two lenses... even this makes a differnce of 5 inches to the projected picture
i will post pictures as soon as i have finished my second projector with and without additional lense... i hope this will be next weekend
i am using a 3 lense ohp optic. the problem is the focal length is too short, that means the picture is too big at a distance of 8,75 ft to the screen...
the idea is to take a lense from eyeglasses at a certain dioptrin in additon to the ohp optic; i explained how to calculate that dioptrien number a few posts ago...
and used the program from the site prjctr_builder discovered...
the default setup is to put the lense right in front of the ohp optic, and by increasing and decreasing the distance it works like a zoom, because when there is room between the ohp lense and the eyeglass the focal length decreases and that means the picture goes wider... i am talking about max 0.8 inches between that two lenses... even this makes a differnce of 5 inches to the projected picture
i will post pictures as soon as i have finished my second projector with and without additional lense... i hope this will be next weekend
Slize,
Is the conclusion that the dioptrin aditional lens needs to be a convex concave eyeglass still or something else?
Is the conclusion that the dioptrin aditional lens needs to be a convex concave eyeglass still or something else?
dracul
please read the previous posts (site 106 and 107) and you'll get all the answers...
especially post #1590 + #1602 + #1603
please read the previous posts (site 106 and 107) and you'll get all the answers...
especially post #1590 + #1602 + #1603
So I want to use Alans 80mm diameter projection lens but the optic stores in my area only seem to carry 65mm diameter dioptrins. I really need 80mm diameter for no cropping to occur dont I? When can I order this online ? Alan do you have any sources near where you are?
I don't have any good lens sources locally that I know of, but I will definitely start looking. Also, I'm having the condencer lenses made for me, so maybe if these newer lenses that you are all talking about really do work, then I can possibly have some of those made too.
Coincidentally, I tried using a 6" concave lens as a reduction lens so that I could use my projector further from the wall and it actually worked! The lens was just an $8 from www.surplusshed.com. It did distort the shape of the image very slightly though, but it didn't distort enough to make objects on the image look strange (it just simply made the edge of the image not quite straight). The addition of this lens before the projection lens (the 80mm triplet) made the image roughly 1/2 the original size. As soon as I get my projector working again I'll measure this effect with a tape measure and also take some pictures of it too now that my camera is working again.
Coincidentally, I tried using a 6" concave lens as a reduction lens so that I could use my projector further from the wall and it actually worked! The lens was just an $8 from www.surplusshed.com. It did distort the shape of the image very slightly though, but it didn't distort enough to make objects on the image look strange (it just simply made the edge of the image not quite straight). The addition of this lens before the projection lens (the 80mm triplet) made the image roughly 1/2 the original size. As soon as I get my projector working again I'll measure this effect with a tape measure and also take some pictures of it too now that my camera is working again.
you can get them lenses where you can get eyeglasses... is that so hard to understand? it is a normal eyeglasses... and the diameter has nothing to do with dioptrien... dioptrin is 1 divided by the focal length of a lense in meters...
I went to a eyeglass store and they showed me a 0.75 dioptrin organic lens. It was only 65mm diameter. If I place this infront of my 80mm diameter projection lens will the image not be cropped?
dracul
don't know about that but i don't think so, as 80mm diameter for an optic is really big...
BTW what focal lenght is your 80 diameter??? i see you didn't get it, how to calculate the dioptrin YOU need... because you tell me something about a 0.75 dioptrin glass. first of all I took a -0,75 dioptrin glass and the focal length of my lense is 290 mm and wanted a 1.54 m projected picture at a distance of 2.4m...
and for example prjctr_builder would need -1.125 dioptrin glass because his existing lense has 320 mm fl for his specifications...
so PLEASE DON'T go and buy a -0.75 dioptrin eyeglass just because it worked for me... make you own calculations and you will get the lense you'll need...
the basic idea is to use eyeglasses because they can be calculated and they are cheap...
just take the example i made and you will get your dioptrin right... and talking of 0.75 dioptrin, this would make the existing focal length of your 80 dia lense only bigger and that would mean you will even get a BIGGER picture
so please read the post and read 'em carefully and switch your brain on and once again you'll get all the answers...
don't know about that but i don't think so, as 80mm diameter for an optic is really big...
BTW what focal lenght is your 80 diameter??? i see you didn't get it, how to calculate the dioptrin YOU need... because you tell me something about a 0.75 dioptrin glass. first of all I took a -0,75 dioptrin glass and the focal length of my lense is 290 mm and wanted a 1.54 m projected picture at a distance of 2.4m...
and for example prjctr_builder would need -1.125 dioptrin glass because his existing lense has 320 mm fl for his specifications...
so PLEASE DON'T go and buy a -0.75 dioptrin eyeglass just because it worked for me... make you own calculations and you will get the lense you'll need...
the basic idea is to use eyeglasses because they can be calculated and they are cheap...
just take the example i made and you will get your dioptrin right... and talking of 0.75 dioptrin, this would make the existing focal length of your 80 dia lense only bigger and that would mean you will even get a BIGGER picture
so please read the post and read 'em carefully and switch your brain on and once again you'll get all the answers...
Re: dracul
I understand that, but I work and take classes during the day, and I also live in a very small town, so it's not that convenient for me to get parts from an eyeglasses store that is only open until 6pm.
slize said:
I understand that, but I work and take classes during the day, and I also live in a very small town, so it's not that convenient for me to get parts from an eyeglasses store that is only open until 6pm.
Slize,
I did do my own calculations and ended up with a positive 0.66 result. I know it should have been negative but I got positive.
1/0.317 (focal lenght of my lens from diylabs)
1/0.423(focal length of desired lens)
1-2 = some negative number (but not in my case) . Are these not the instructions?
I did do my own calculations and ended up with a positive 0.66 result. I know it should have been negative but I got positive.
1/0.317 (focal lenght of my lens from diylabs)
1/0.423(focal length of desired lens)
1-2 = some negative number (but not in my case) . Are these not the instructions?
Alright its 2-1 or the ideal focal length dioptrin minus your actual lens dioption. I could swear I saw someone post instructions as 1-2. Never mind. I appologize. Brain turned ON now.
80mm diameter is the lens from Alan diylabs. Its focal length is around 317mm I think. Bigger diameter the better is it not? More light etc.....
80mm diameter is the lens from Alan diylabs. Its focal length is around 317mm I think. Bigger diameter the better is it not? More light etc.....
reflector
I don't mean to change the subject away from the eyeglass lens stuff, but I need some ideas/advice for a reflector.
prjctr_builder:
Any luck on getting your reflector plans/diagram up? You mentioned doing that a while back, and I was wondering if you were still planning on doing that.
I don't mean to change the subject away from the eyeglass lens stuff, but I need some ideas/advice for a reflector.
prjctr_builder:
Any luck on getting your reflector plans/diagram up? You mentioned doing that a while back, and I was wondering if you were still planning on doing that.