Just so I'll know for sure...
I'm building my projector. When you guys talk about one of the split fresnels being 13" from the light source, and the second fresnel being 9.8" ... is that 9.8" on the other side of the LCD?
I'm replicating Cruser's light tube, I'm a noob and I think it's a brillant idea. I just don't have a handle on the distance's yet. I
Tom
I'm building my projector. When you guys talk about one of the split fresnels being 13" from the light source, and the second fresnel being 9.8" ... is that 9.8" on the other side of the LCD?
I'm replicating Cruser's light tube, I'm a noob and I think it's a brillant idea. I just don't have a handle on the distance's yet. I
Tom
If you are using a diylabs Fresnel you have your Light source then you place your rear Fresnel lens about 8.9 inches away from the light, then a inch or 2 of space from your rear Fresnel lens put your lcd panel, then place your front Fresnel lens another inch or 2 away from your lcd and then put your triplet or other focusing lens in front of the front Fresnel close to its focal length (around 14 inchs or so if we are talking about the diylabs ones) and move it back and forth till it focuses. Look at Karnage’s post on the first page of this tread he has a little picture that should help illustrate.
Light - 8.9inch space - First Fresnel – 1-2 inch space – LCD – 1-2 inch space – front Fresnel – 14 inches or so of space - triplet lens.
Light - 8.9inch space - First Fresnel – 1-2 inch space – LCD – 1-2 inch space – front Fresnel – 14 inches or so of space - triplet lens.
ok ok im not gonna push the isue anymore
the only reason i steped up and said anything was because of jcb
telling people that they could never focus the image and you will always have rings on the image that statment is simply NOT TRUE!! and i dont want anyone to get false facts that just confuse people
brainchild i respect your opinion because you have constructed
and posted your results here on the fourm and i must say they
were awesome
to see good results with a large format mh bulb and no reflector
"GFJ" man
i think the reason you didnt see a difference in brightness was
because of that BIG A** FU**IN SUN you have in your pj you probily dont need a fresnel at all 😀
so im done arguing about something that is well just personal
prefrence like you said if you like what you see do it
if not dont do it
but dont lie to people thats just not right we are all here to learn
the only reason i steped up and said anything was because of jcb
telling people that they could never focus the image and you will always have rings on the image that statment is simply NOT TRUE!! and i dont want anyone to get false facts that just confuse people
brainchild i respect your opinion because you have constructed
and posted your results here on the fourm and i must say they
were awesome
to see good results with a large format mh bulb and no reflector
"GFJ" man
i think the reason you didnt see a difference in brightness was
because of that BIG A** FU**IN SUN you have in your pj you probily dont need a fresnel at all 😀
so im done arguing about something that is well just personal
prefrence like you said if you like what you see do it
if not dont do it
but dont lie to people thats just not right we are all here to learn
Mixed Messages
I believe these two posts conflict. Which is the "correct" way to set up the fresnel lenses? Brainchild's results are awesome, and Space Ninja, your results are pretty sharp, so I was wondering if one way is better than the other. I would assume that having the longer focal point on the side of the triplet would allow a longer throw distance from the triplet, because of the angle that the light is entering the lens. I could be way off base here, but let me know what you think.
Thanks,
Steve
"If you are using a diylabs Fresnel you have your Light source then you place your rear Fresnel lens about 8.9 inches away from the light, then a inch or 2 of space from your rear Fresnel lens put your lcd panel, then place your front Fresnel lens another inch or 2 away from your lcd and then put your triplet or other focusing lens in front of the front Fresnel close to its focal length (around 14 inchs or so if we are talking about the diylabs ones) and move it back and forth till it focuses. Look at Karnage’s post on the first page of this tread he has a little picture that should help illustrate.
Light - 8.9inch space - First Fresnel – 1-2 inch space – LCD – 1-2 inch space – front Fresnel – 14 inches or so of space - triplet lens."--Space Ninja
"The bulb should be located close to the focus of your collimating fresnel, and the objective lens should be located slightly before the focus of your condensing fresnel. If you have a 14"FL collimating fresnel you would want your bulb close to 14" away. If you've already built your enclosure and you now need shorter FL optics, I would suggest picking up a couple of 9"FL fresnels, cutting them down to size and seeing if you can make them work with your rig. Alan and others have the 'back' shorter FL fresnels. The general consensus is that a longer FL fresnel (14") is best for the condensing side of your projector, but if you've built your enclosure you can't do that..."--Brainchild
I believe these two posts conflict. Which is the "correct" way to set up the fresnel lenses? Brainchild's results are awesome, and Space Ninja, your results are pretty sharp, so I was wondering if one way is better than the other. I would assume that having the longer focal point on the side of the triplet would allow a longer throw distance from the triplet, because of the angle that the light is entering the lens. I could be way off base here, but let me know what you think.
Thanks,
Steve
"If you are using a diylabs Fresnel you have your Light source then you place your rear Fresnel lens about 8.9 inches away from the light, then a inch or 2 of space from your rear Fresnel lens put your lcd panel, then place your front Fresnel lens another inch or 2 away from your lcd and then put your triplet or other focusing lens in front of the front Fresnel close to its focal length (around 14 inchs or so if we are talking about the diylabs ones) and move it back and forth till it focuses. Look at Karnage’s post on the first page of this tread he has a little picture that should help illustrate.
Light - 8.9inch space - First Fresnel – 1-2 inch space – LCD – 1-2 inch space – front Fresnel – 14 inches or so of space - triplet lens."--Space Ninja
"The bulb should be located close to the focus of your collimating fresnel, and the objective lens should be located slightly before the focus of your condensing fresnel. If you have a 14"FL collimating fresnel you would want your bulb close to 14" away. If you've already built your enclosure and you now need shorter FL optics, I would suggest picking up a couple of 9"FL fresnels, cutting them down to size and seeing if you can make them work with your rig. Alan and others have the 'back' shorter FL fresnels. The general consensus is that a longer FL fresnel (14") is best for the condensing side of your projector, but if you've built your enclosure you can't do that..."--Brainchild
w00t
Spin, It seems evident that either will work, try both and see what you like.
errata: I stupidly called a 'collector' a 'condensor'.....for the record, a collimator and condensor are the same, the front fresnel is a collector..the weed is good though. 😉
Spin, It seems evident that either will work, try both and see what you like.
errata: I stupidly called a 'collector' a 'condensor'.....for the record, a collimator and condensor are the same, the front fresnel is a collector..the weed is good though. 😉
I never lied to anyone. Compared to the focused image I get with the fresnels mounted behind the LCD... any alignment where a fresnel is put in front blurrs MY image. OK. 99% of people who see it dont notice the blurring...l but I do. I get better results mounted behind.
Part of the problem with these setups is personal preference and the give and take of what you can afford and what you think looks good.
Part of the problem with these setups is personal preference and the give and take of what you can afford and what you think looks good.
jcbklyny , what are you using for FL fresnels and pj lens?
Seems I have the wrong combination to place my fresnels before the lcd? All I keep getting is the lens projected on the screen.
Fresnel 1 ,8.9 inch FL
Fresnel 2 ,13 inches FL
PJ 13 inches FL
Seems I have the wrong combination to place my fresnels before the lcd? All I keep getting is the lens projected on the screen.
Fresnel 1 ,8.9 inch FL
Fresnel 2 ,13 inches FL
PJ 13 inches FL
why is 2 fresnels better than one? i just have one that makes a cone of light throught the LCD and onto the focusing lens. the only effect of fresnels that i understand is getting the light right, and as long as the lens is well placed receiving from the LCD then the image will be crisp.
You allway focus to LCD not to the fresnel. If the two fresnel and the LCD are too close to each other - whether the fresnel is between the LCD and PJ lens or behind the LCD, it doesn't matter.
In fact, you can and sometimes must (like with the AUO M150XN05 TFT panel, but not so much with the CMV 1515 panel, A150X1-T05 or whatever it is) put the fresnel in the image path to get a decent picture. However, it works only because and when
1) the light rays coming to fresnel are collimated
2) the fresnel has 'grooves out' (meaning towards the light source)
3) the PJ lens is focused to LCD panel
In this kind of arrangement there is no ghosting or other symptoms of usual disadvantages of the fresnels.
In my setup I tilt both the LCD (to get the best contrast) and the fresnel (for keystone correction). Because of LCD correction I also has to tilt the PJ lens to keep it parallel to LCD, otherwise the image isn't focused on the screen. Which IMHO proves that the PJ must be focused to LCD but not to the fresnel.
In fact, you can and sometimes must (like with the AUO M150XN05 TFT panel, but not so much with the CMV 1515 panel, A150X1-T05 or whatever it is) put the fresnel in the image path to get a decent picture. However, it works only because and when
1) the light rays coming to fresnel are collimated
2) the fresnel has 'grooves out' (meaning towards the light source)
3) the PJ lens is focused to LCD panel
In this kind of arrangement there is no ghosting or other symptoms of usual disadvantages of the fresnels.
In my setup I tilt both the LCD (to get the best contrast) and the fresnel (for keystone correction). Because of LCD correction I also has to tilt the PJ lens to keep it parallel to LCD, otherwise the image isn't focused on the screen. Which IMHO proves that the PJ must be focused to LCD but not to the fresnel.
Attachments
another rule to follow is the lens must always be square to the lcd or what ever that is your projecting or u will never get a evenly focused image, a singlet is good for testing this as the majority of decent singlets are so sensitive that 1mm of movement can make the image ghost, out of focus on the side or edge out, i beleive a triplet has more give but either way this rule of the lens to the panel must be perfectly square, if u want a keystone tilt the front frensel, if no front frensel then tilt a mirror if you have one, if not well the good old nvida drivers will have to supliment you with a digital keystone, yess mehin u are correct we are all out to project 1 thing, the lcd, not a light bulb, not a reflector nor any frensel, but however with frensels we do need to use that focal for the light, even if the focal of the frensel is out by an inch or 2 we can get away with this as frensels do have plenty of leeway and not only that but we are using it to transmit light not an image.
trev
trev
mehlin the second fresnel looks assymetrical. a symetrical fresnel here would focus beside the lens
Dracul
i had the same problem i built the diy projector i found that you can ditch the wood dowls, lens is too far away i actually mounted my board with lense attached to a small board that i just move back and forth inside the projector and this works fine i also used only 1 mirror angled over top of lcd and just one fresnel much like an overhead projector and im getting really nice picture easy to focus and have had hours of enjoyment so far, i hope to post pics one day , but i just basically followed the k.i.s.s rules thinkin about adding a condensor lens still mainly best veiwing in the dark but have my screen hangin over picture window with nothing but a quilt behind it and can still see picture even during day.
got to get me some blackout cloth and will make veiwing durin day even better im sure anyway good luck
i had the same problem i built the diy projector i found that you can ditch the wood dowls, lens is too far away i actually mounted my board with lense attached to a small board that i just move back and forth inside the projector and this works fine i also used only 1 mirror angled over top of lcd and just one fresnel much like an overhead projector and im getting really nice picture easy to focus and have had hours of enjoyment so far, i hope to post pics one day , but i just basically followed the k.i.s.s rules thinkin about adding a condensor lens still mainly best veiwing in the dark but have my screen hangin over picture window with nothing but a quilt behind it and can still see picture even during day.
got to get me some blackout cloth and will make veiwing durin day even better im sure anyway good luckNot sure what your talking about here. Can you explain?
So you are using one of the split fresnels or one fresnel that has both a back FL and a different front FL? Can you be more specific?
And your fresnel than is not in the image path or between light and LCD? What are your distances and what FL is your PJ lens?
using diylabs fresnel not split and built the mk1 design that had wood dowels holding triplett lens but was too far outside the box and all i got was triplet ring and no picture but when put inside box picture was great.
Modification Question
Is there any reason I can't take the 575W metal halide lamp, fixtures and ballast from inside an Elmo HP-305A Solar Deluxe and re-install it into my DYI enclosure?
Tom
Is there any reason I can't take the 575W metal halide lamp, fixtures and ballast from inside an Elmo HP-305A Solar Deluxe and re-install it into my DYI enclosure?
Tom
tmitch007
nope but watch the heat and make sure u put the wires on the right way round, if your enclosure is made out of wood watch the heat as it will burn the wood, try to insulate the wood.
trev
nope but watch the heat and make sure u put the wires on the right way round, if your enclosure is made out of wood watch the heat as it will burn the wood, try to insulate the wood.
trev
Thanks Ace... my plan is to use Cruser's light tube configuration... I've not seen the "guts" of the Elmo yet, so I don't really know if it will be adaptable to the light tube setup.
BTW, I shipped the bad BenQ 567s that I bought on Ebay back to the seller, and he said that he was refunding my $232.50 the same day that he receives the LCD.
Thanks-
BTW, I shipped the bad BenQ 567s that I bought on Ebay back to the seller, and he said that he was refunding my $232.50 the same day that he receives the LCD.
Thanks-
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