I finally have my projector up and running. It is fairly well in complete darkness but I still think it should be a little brighter, it doesn't look as good as my OHP but that could be because the halogen bulb has CRI:100.

It is a vertical build with:
Samsung 150mp (anti-glare removed)
2 330mm fresnels glued together (from an overhead projector)
18" beseler series 3 triplet
A BT37 Sylvania bulb 4200k CRI:65
A reflector that looks like a hubcap
A mirror from the inside of the overhead projector (trapazoid shaped)

My fresnels are about 8 1/2 - 9 inches from the bulb and gets about perfectly lit corners contrary to where i thought they would be (330+330=660-~500= 160mm) .. 160mm from the bulb has only the middle of the lcd lit.

I have these parts:
220/330 and triplet from LL
light engine from OHP 300w 24v (50hr life)
M59 ballast coil and core


My first question is if the mirror inside the overhead projector (not the small one by the triplet) is a front surface mirror? and if not, how much more effective would a Front surface mirror be?

I was wondering with the distance from my bulb to my fresnels (~8-9 inches) if it would be possible to use a pre-condenser lens with my setup similar to a 220/550 setup.

Also if i get the LL65k bulb and the pro-reflector which should increase my light by about 50% and overdrive it at 550w..i should have nearly double the output I do now with better color and a higher CRI right?

What plan of action should I go from here to get the most output from my projector with the least amount of money?

Thanks

well, the simplest thing to do to increase your light is to use the 220/330 fresnels, your corners will be dimmer but you will have umm...50% more lumens(or is it twice? that whole invers square thing confuses me..I think its twice the lumens) and if you watch a lot of 16:9 widescreen movies, it will be pretty decent... I think your colors will be much better with the ll65k bulb, plus you can then use the pro reflector so theres an increase also,though I don't know the lumens of your bt37 bulb, but I'm guessing that its in the same range as the ll 65k bulb,,percentage wise its hard to say though.... so try the 220/330 combo first, since you already have them thats your best and cheapest shot...
as for the mirror, it should be easy to tell if its a first surface mirror just by looking at it, it will either have glass over the reflective surface or not, I would guess it is a fs mirror....

and yes, with the 330/330 setup you can use a precondenser to increase your brightness, not sure which one would be best though..use dazzz' calculator to figure that out

Im using the 330's with a 18" triplet so I'm adding the focal lenghts of the fresnels 330+330-~500(triplet focal)=160mm from light. This is too close so I move it to about 8-9inches away from the light to get even corners this is about the same distance as a 220mm fresnel(8.6in). So what your saying is a 220/330 with a standard triplet will be brighter then a 330/330 about 8 inches away from light and a 18" triplet?
Thanks

How are you using a 18" (457mm) triplet with a 330mm field fresnel? That can't possibly work, can it? I have a 330mm field fresnel also, but I can't even get my 14" (355mm) triplet to work properly. Can you post a screenshot and a picture of your projector's internals please? I am most curious.

Also, I don't understand the math behind adding the FL's of your fresnels and subtracting the FL of your triplet to get bulb placement distance. This is the first time I have seen this done. I thought we simply placed the bulb at or around the FL of the rear fresnel, regardless of the FL of the front fresnel or triplet.

well, I would think he would lose a lot of light since at 330mm from the front fresnel the collected light will start diverging and depending on the distance between the fresnel and the triplet there must be a lot of light spillage... is there a big ring of light around your triplet crazyDIY? if so theres lost light, I didn't even catch thta the first read thru... and yeah votey.... I agree, the lamp should be placed somewhere near the FL of the rear fresnel, usually a bit closer, I would guess its good at 9" to make up for the front fresnel being sucha a short FL.....

The 330+330-500=160 is an idea i got from arizonavideo, it has been used with success with diyeitor and christmasgt I believe before he switched to a 220/550. Mikyd1954 you are right about the light converging before hitting the lcd which may cause for slightly dimmer corners, but for 16:9 movies it works fine. The problem I have with the 330/330 is if I put the fresnels at the 160mm mark, the arc size by the time it gets to the triplet is bigger than the triplet and the farther i move the fresnels from the bulb the smaller it gets.

1. I did get my hands on a Venture ED28 bulb with similar specs(36000 lumens, CRI:65) so now I think I should be able to use Arizonavideo's 6x9 condenser lens right?

2. My bulb is now at about 10in away from the fresnels because mikyd1954 was right that there was a lot of light spillage aroudn the triplet.. Now since it is about 10in that should mean it is dimmer then a 220/550 setup, if I move the fresnels closer to the bulb and light is spilling around the triplet, then I'm really not gaining any brightness from it being closer to the bulb right? just dimmer corners"

So with my setup right now I was wondering which would be the best option to go from here.

3. I could get the LL65k bulb(better CRI definitely) and overdrive it to 550w with a pro-reflector and nearly have double the brightness I have now right? (an extra 150w +50% pro-reflector) and eventually condenser possibly.

4. Get a 220/550 set so the fresnels can be closer to the lcd and the triplet won't have light spillage around it? (if I understand it is the 330/330 that is causing the arc to be too big) Also does 3d lens cut fresnels because they might be too big for my box.

5. Keep the setup I have now and get a Napkin Ring or similar reflector that works with an ED28 and a 6x9 condenser lens?(if it will work with a 330/330 setup)

I don't want to spend too much more money on this project. I want to have the best brightness at the lowest cost. I'm kinda leaning towards the new bulb and pro-reflector. Because of the huge CRI jump. Elken showed how a 150w bulb can nearly look as good when the CRI is only a little higher (I think 90 with
the HQI and 98 with the CDM.) That may be a huge difference going from CRI:65 to 91.

Sorry for the disorganization I just have a lot of questions and different ways I could go about this project. It looks great right now, but why not upgrade if it can look even better?

I have emailed 3dlens before, and was told that they will not pre-cut fresnels. You will have to cut them to the proper size you need for your projector.

I think that with using an 18" triplet, I would definitely go with the 220/550 or 220/650 pro fresnel set up (which is actually more like 610mm focal length, and Jonjandran uses this fresnel with an 18" triplet and says it works great). The 650 pro from LL will be cheaper than the 550 from 3dlens (unless you don't live in the U.S., after shipping to the US it will cost you $40).

I don't see any reason to use a 330mm rear fresnel unless you're using a condenser lens with an 18" triplet, you are losing a lot of brightness right there. Certainly a condenser would help, but you said you're trying to keep costs low, and I believe buying the proper fresnels would be cheaper than purchasing a pyrex condenser.

I think you also need to listen to mikyd some more when it comes to the issue of trying to use a 330 front fresnel with an 18" triplet. Like he and Votey have mentioned, I don't see how you can properly get a focused image with this mismatch in optics. The 330mm fresnel's focal length is trying to focus an image at approx. 330mm from it's source, but the triplet you're using needs to be approx. 457mm away from it's source to be properly focused; therefore the light and image from your lcd is trying to properly focusing the image from your fresnel before it can reach the triplet. This will cause your light to scatter and invert itself before it will reach your triplet. And if you placed the 18" triplet around 330mm away from the fresnel so that you don't lose your focused light, I'd be amazed if you could get a focused image on your screen.

Bottom line, I'd buy some new fresnels and a good reflector, and I think this may help out your issues tremendously.

Although the LL T15 bulb and the pro reflector could help a lot too, but I don't see why you would need to over drive it to 550w (almost everyone using this bulb is keeping it at the normal wattage and are getting fine results in terms of brightness).

if you're going to be watching mostly 16:9 and wider aspect ration movies, the 220/550 combo is the best and cheapest solution...... remember the front fresnel has nothing to do with the focusing of the picture itself, the only reason is as a light collector, to make best use of its light collecting , there needs to be a very close match between the FL of the triplet and the front fresnel.... the 220mm rear fresnel will gather twice as much light from the lamp as the 330mm rear fresnel will ..... albiet the corners of the image will be dimmer but people have lived with that happily for years..... and to backtrack a little, if you have a 330mm rear fresnel, the absolute cheapest brightness increase would be a $8.00 (polus 5 for shipping) 4.5x6.5 condenser form surplusshed.com ..... best idea is for you to come up with a budget for the brightness increase and then that will set your options more distinctly
edit: well, its the cheapest if you can keep it from cracking that is
do yourself a favor, get the pro fresnels if you can afford it, before you do anything else..

I think what you may be mistaking is since I have a 330 collector and field is that my collector is 330 from the bulb, it is not. Usually it it around 8 or 9 inches from the bulb which is the equivilent distance of a 220 collector, but I think this is causing the arc to be bigger at the triplet. Another thing I want to clear up is that a 220/550 with a 18" triplet is brighter than a 220/330 standard triplet correct?

The 330/330 pair that I'm using now can have basically edge to edge brightness, this works somehow because u put them before there actual focal length of 330mm. If they are 330mm away it will focus at the normal 330mm mark, and if you use a 18" triplet it will only focus the center of the image for some reason.

My question is so a 330/330 placed at the same distance from the bulb as a 220/550 will be dimmer on the basis of the arc size at the triplet right?

The size of my arc now is barely bigger than my triplet so if I get the new bulb which has a smaller arc it should practically be the same right?

The 330mm/330mm setup works but there is a price to pay from having the lamp moved away from the 330mm mark.

The fresnel will have more "shading" the further away you move from the 330mm mark. You really need to get the 550mm front fresnel. There is a guy that has them on e-bay too.


You have both a 330mm and a 220mm rear. With a large shell lamp like you have just go with a 220mm untill you get a small shell light setup. The large shell lamps make it hard to find a good reflector and the condenser lens has to be too far away.

Then you can go with a pro reflector , T15, condenser lens setup. With a 15" LCD you can keep the 220mm rear fresnel and use a 6x9 condenser too.

If you are using an unsplit fresnel combination then the focal length will chance because you are combining the focal properties of the fresnels, using the split fresnels then you use the focal lenth of each fresnel.

Maybe I didn't do a good enough job trying to explain and help you with your questions in my first post, so I will attempt again.

If your collector/collminator/rear fresnel's focal length is 330mm, it needs to be roughly 330mm away from the bulb, idealy possibly more like 320mm way.
If your rear fresnel's focal length is 220mm, you should place it 210-220mm away from your bulb.
Placing your 330mm rear fresnel only 220mm away from your lcd is going to cause the light to be spread out larger than the size of your fresnel or lcd, therefore giving you more stray light. The pictures in this post should explain what I'm trying to say (refer to the second picture):
http://www.lumenlab.com/forums/index.php?s...c=15625&hl=

When you ask if a 220/550 with a 18" triplet is brighter than a 220/330 standard triplet, this is kind of a trick question. Because the standard triplet (who's focal length is 320mm) can be placed closer to the bulb and lcd, the light doesn't have to travel as far, giving a decently bright image.
With the 18" triplet (who's focal length is 457.2mm), it has to be placed farther away from the bulb and lcd, causing light to have to travel a greater distance, but because the 18" triplet is much larger in diameter, it has the ability to capture more light, and some people have reported to get a brighter image.

Ok so because I'm getting more stray light with the 330/330 I will get more brightness with a 220/550. I understand that the 220/550 is the best setup, but I am completely fine with the light evenness and the picture quality, the only thing that is partially bugging me is the brightness. My picture is fairly fine, but I have to turn the contrast up on the monitor which causes it to look a little weird.
1. The 220 fresnel I have right now is pretty beat up, its got some scratches on it and its pretty dirty, will this effect the image at all?
2. Also, how much, if at all, will a 220/550 be brighter then my current setup?
3. And will the LL bulb at 550w and a pro reflector double my brightness?

Where I'm at right now is if my dirty 220 won't effect my image too much, then about $40 for a 550 fresnel, or $25 for LL 650mm (dunno how much brightness increase) or $48+shipping for the LL pro fresnel set.
-or-
$50 bulb + $15 reflector + shipping, for in theory about double brightness.

I know that a 220/550 is definitely a better setup then my 330/330 but how much increase in brightness will it give me ultimately.

Thanks