I have now finished my diy-projector, consisting of a 15" TFT and a 150W cdm-t bulb, and a new light engine that use most of the lumens the bulb produce (more info about how the lightengine works you can find in the thread "videoprojector part II" page 116), I´m satisfied with the picture quality and the brightness. But the diy projector is too big and beautiful isn´t it. It looks like a nuclear-missile, And if I mount it in the roof I will get pretty flat if it falls down 
So I have thought of an other idea: Buy a cheap commercialprojector, people are selling them cheap sometimes because they can´t afford to buy a new bulb. Replace the expensive UHP-bulb (Ulta High Preformance) with a cheaper HQI-T 150W bulb, of course I have to use an external ballast. My question is what ANSI-lumen can I expect if I do that ?
Let say the commercialprojector use a 150W UHP-bulb and give 1000 ANSI-lumen with that.
Is the UHP-bulb so much more effective than a HQI-bulb ?
Will it be brighter than my diy-projector ?
So I have thought of an other idea: Buy a cheap commercialprojector, people are selling them cheap sometimes because they can´t afford to buy a new bulb. Replace the expensive UHP-bulb (Ulta High Preformance) with a cheaper HQI-T 150W bulb, of course I have to use an external ballast. My question is what ANSI-lumen can I expect if I do that ?
Let say the commercialprojector use a 150W UHP-bulb and give 1000 ANSI-lumen with that.
Is the UHP-bulb so much more effective than a HQI-bulb ?
Will it be brighter than my diy-projector ?
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I think the trick will be to
1.trick the projector into thinking the bulb is fine
2.Focusing the parabolic reflector from the old bulb with you new, cheaper replacment. Kinda like your picture. this would give you about the same ansi lumens (assuming the bulb your using has the same lumen output as what its replacing)
3.Fit you cheaper and probally larger bulb into the space intended for that tiny blub.
If you could overcome these problems this would be a very cost-effictive way to go with a DIY projector, and alot nicer too. Plus the pj would be BEHIND the seating area.
Let me know if you try this, i'd be very interested in the results!
1.trick the projector into thinking the bulb is fine
2.Focusing the parabolic reflector from the old bulb with you new, cheaper replacment. Kinda like your picture. this would give you about the same ansi lumens (assuming the bulb your using has the same lumen output as what its replacing)
3.Fit you cheaper and probally larger bulb into the space intended for that tiny blub.
If you could overcome these problems this would be a very cost-effictive way to go with a DIY projector, and alot nicer too. Plus the pj would be BEHIND the seating area.
Let me know if you try this, i'd be very interested in the results!
i tried to do this with my proxima dp2800. However space is very limited and the light path is far from perfect(dp2800 uses about 4 first surface mirrors ,and the beast is a hell of a difficult machine to get apart (never seen a electronic device so difficult to dissasemble). Maybe in the future i take the thing apart and put it into a new housing. However, i think my lcd-controller is a little screwed up . There is some kind of raster over the projected image (its not the fresnell) .It's very strange and i don't know what it is.
If I can in some how put the HQI-bulb in right place and focus it, and I mayby need to put the bulb a little outside the commercialcase in a extra box, but does anyone know if I can turn of the message "Please change the bulb" that I have seen in some shop ?
Which projector will be brightest and the best choich ?
1. Diy 7" TFT lilliput, with a 150W HQI, 200:1 contrast, 800*480 res.
2. Cheap commercialprojector 3 panels TFT 400:1 contrast, 800*600 res, change bulb to a 150W HQI.
I have seen some old projectors on the market that use one 6" TFT panel and a 250W HID, and this this thing only put out 250 ANSI lumens, wouldn´t the 7" TFT lilliput thing get less bright ?
Which projector will be brightest and the best choich ?
1. Diy 7" TFT lilliput, with a 150W HQI, 200:1 contrast, 800*480 res.
2. Cheap commercialprojector 3 panels TFT 400:1 contrast, 800*600 res, change bulb to a 150W HQI.
I have seen some old projectors on the market that use one 6" TFT panel and a 250W HID, and this this thing only put out 250 ANSI lumens, wouldn´t the 7" TFT lilliput thing get less bright ?
Yes I think we can do it.
I finally bought a cheap commercialprojector, I couldn´t resist, the price was only what you pay for two 15" tft monitors. Well the UHP-lamp will last in 1500h and a the price for a new one is the same as for a new 15" tft. So of course I will not buy a new lamp-unit.
I found out that a UHP-bulb is actully the same as a HID short arc lamp, so the only diffrents between a HQI and a UHP is that the arc is smaller in the UHP, the light output is the same.
The UHP-lamp unit puts out a parallel beam that is 50mm wide. I think it´s not so difficult to build a HQI-light unit that puts out a parallel beam of that size. And because the light is parallel we can use a mirror so we can place the light-unit outside the pj-case.
I finally bought a cheap commercialprojector, I couldn´t resist, the price was only what you pay for two 15" tft monitors. Well the UHP-lamp will last in 1500h and a the price for a new one is the same as for a new 15" tft. So of course I will not buy a new lamp-unit.
I found out that a UHP-bulb is actully the same as a HID short arc lamp, so the only diffrents between a HQI and a UHP is that the arc is smaller in the UHP, the light output is the same.
The UHP-lamp unit puts out a parallel beam that is 50mm wide. I think it´s not so difficult to build a HQI-light unit that puts out a parallel beam of that size. And because the light is parallel we can use a mirror so we can place the light-unit outside the pj-case.
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Which projector will be brightest and the best choich ?
I asked before which of the two choiches below that are the most worth to buy.
1. Diy 7" TFT lilliput, with a 150W-250W HQI, 200:1 contrast, 800*480 res.
2. Cheap used commercialprojector 3 panels TFT 400:1 contrast, 800*600 res, change bulb to a 150W HQI.
I did a very intressting comparision between the two choiches.
The pictures to the right are the diy-projector and to the left the commercialprojector. The pictures up is with the lights on, and down it´s off. The diy-projector, consisting of a 15" TFT and a 150W cdm-t bulb, and the new light engine with a PAR30-reflector. Because I use the PAR30 reflector it will be equal to a 7" -design.
The pictures are taken with the same camra, same dvd-player, same surrounding light and same screen-size 100". My camra don´t like dark pictures, so what seems dark is not so dark. Which would you choose ?
I asked before which of the two choiches below that are the most worth to buy.
1. Diy 7" TFT lilliput, with a 150W-250W HQI, 200:1 contrast, 800*480 res.
2. Cheap used commercialprojector 3 panels TFT 400:1 contrast, 800*600 res, change bulb to a 150W HQI.
I did a very intressting comparision between the two choiches.
The pictures to the right are the diy-projector and to the left the commercialprojector. The pictures up is with the lights on, and down it´s off. The diy-projector, consisting of a 15" TFT and a 150W cdm-t bulb, and the new light engine with a PAR30-reflector. Because I use the PAR30 reflector it will be equal to a 7" -design.
The pictures are taken with the same camra, same dvd-player, same surrounding light and same screen-size 100". My camra don´t like dark pictures, so what seems dark is not so dark. Which would you choose ?
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The reason the pro projector is brighter is a few reasons, 1 is a more refined light engine, 2 is because it has 3 lcds i beleive this gives us 3x the brightness as 3x 10% = 30% from source though i could be wrong on this and 4 maybe your optics are out, and 5 the lumens on pro projector bulbs are abit more then the cdm-t, not only that but you are not using a condenser in your setup and this will yeald u 2x the brightness atleast!. I think basically u cant compare a pro projector that has 3 lcd's to a diy projector that only has 1, the 3 lcd's do make a difference to the brightness, also if you wer to use the same lamp in both projectors then you would have a more acurate reading on weather the pro one is brighter then the diy projector, another reason the pro projector could be brighter in this case is the fact that lighting a 15inch area is spreading more light then in a pro one thats got its light fully condensed into a beam, trust me this makes a very big as i have tried it and use that kind of system in mine projectors hence a reason why i use small lcd's.
Trev
Trev
going on a price comparison of $400 for a bulb every 2000-3000hrs compared to a bulb price of $37 for every 12000hrs yess lol and for your info pro projectors bulbs are brighter hence the lifetime they have, they are tweeked to the maximum light outpput rather then life span, u could get the same light output as a cdm-t as the bulb u have but it would have a life span of roughly the same, and it would be an inconvinience for shop keepers to change a bulb ever 2-3k hrs so they exstend the bulbs life comprimising some of the light where as in projectors they tweak the bulb for a higher light output and have less life, not only that but a reflector in a pro projector is custom made for its light engine so its one hell of alot more eficient then just using a spherical reflector, i just sold a pro projector and beleive me a pro projectors light is brighter, retrofit your projector with a cdm-t and u will see the diff strait off.
Trev
Take a look at stage lights they use 2 condensers to keep the beam intense and condensed on a parabolic reflector design, and with that reflector u have u can change the angle of the beam so u can use a condenser, try a peice of card board over the light to see the reflected angle for ajusting the beam angle.
Trev
A UHP-bulb is the same as a "xenon short arc-bulb" and they are not tweeked to get more bright light, they have shorter life because the distans between the electrodes is shorter, the arc-tube is smaller and a have a very high pressure. The only reason they use that types of bulb is that the arc is smaller and because it´s smaller the arc will be more intensive than the HQI, but the total light output is about the same. Why do they want the arc smaller then ? It´s because it´s more easy to concentrate the light in a straigh beam to the 0.7" tft panel and the projector will be smaller. By the way new UHP-bulbs have a lifetime of 6000h.
Yes I know that they use condensers in stagelight, but the reason they do that is to get the light more even and as you can see on my pictures the screen is a little darker in the corners, and that will be better with condensers, but the brightness will be the same as before.
And I´m pretty sure that the Pro projector will be much brighter than the 7"-diy projector even with a cdm-t bulb.
3 panel against 1.
Pro has microlenses, not avalible on a diy, give 2 times brightness.
oh absolutly as they have a brighter bulb, how do i know this? cos for 1 they dont use any less then 25000lm and 2 ive contacted a indian company who i asked specs on a pro projector bulb, that was 250w and 45000lm with a lifetime of 3000hrs, now unless they are wrong wich i doubt they wouldnt know their product pro projector bulbs are brighter, ive even heard of 380w pro projector bulbs putting out 90000lumens, thats a big pluss for them, so its not only the 3 panel issue but its also their bulb, micro lenses im not sure your talking about maybe its your english but my understanding is a higher scratch and dig spec making the lens more acurate and basically just in a smaller package, to me i think peoples projectors should be brighter then what they are, most of the time things arent lined up properly and their light engine isnt at its full potentional, with that being said i plan to fix this on making pre made light engines available with the RIGHT lenses used for projection in a certian sized aplication, but i think weather you talk pro projectoirs or diy you both have pluss and minus points in each, to me id rather build then buy and i know mines cheaper to run then any pro projector out there on the planet for the same given running time, lumens i dont care about, its just the mesurement of light from the screen reflected back to the veiwer, the more lumens reflected the more ambiant light u can have and still view the image, the less lumens the less ambiant light u can have in the room to veiw, although there is a point where u can not have enough light and the image will look washed out and have bad colouring, i havnt made a projector yet thats had this problem and i dont plan to either, my projector i beleive is the first of its kind in the world being clear plexi in its size and i think thats somthing that makes it different from the pro ones, and thats what i like, somthing different, if i didnt care about diy or was lazy to build or wanted the easy way out then i would have bought a pro one like you have, but once again bulb prices and the cost of repair as manny of these cant be fixed by the average electronics enthusist, as for saying that mine will be darker then a pro projector where did i say it would be brighter then a pro projector? u cant exactly match a 3lcd with a brighter bulb with a single lcd with a less brighter bulb can we? i think the answer is obvious, however u may want to talk to cruser about his machine as his hits neary the 1000ansi lm mark just with 20000lm of source light, now to me thats better then a pro projectors efferts with 3 lcd's.
Trev
I think you have missunderstood me a little, The comparement I did was to show how bright a cheap commercialprojector is with it´s orginal bulb, because people beleve a diy-projector can be over 1000 ANSI-lumens bright with a 250W HQI bulb and that is far from true. With a 1000 ANSI-lumen projector you can watch movie on a screen size of 200" in daylight. I´m not saying that the commercial-projector will be that bright with a cdm-t bulb, but I´m saying that I think it will be brighter than a diy but not how much.
My commercialprojector is around 800 ANSI-lumen, and I think 400-800 ANSI-lumens is good for home-movie, but my contract rate is too low, it should be around 800:1 to be good. At the end of the bulbs life the output will only be around 400 ANSI-lumen and I think that is what I get if I change the bulb to a cdm-t.
Below is a explaning what microlenses are, and why they make the projector brighter, the picture belongs to EPSON.
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