Well Im working on a second projector( hey if one is good 2 is better) so anyways I wanted to know if (1) 400 watt MH is enough to be retrofitted in a OHP or mabe (2) 400 watt MH's? also is there a lot of heat put out by MH's, I have heard it both ways. Thanks for any further insight.
My 175watt MH is about half as hot as my 90watt 30o Halogen spot light.😉 THats the focused light off the bulb through lenses. I use all glass lenses. Low IR and all. Anyhow if you really yamp up the OHP case cooling one will be OK. I think two will be pushing it. Useing maybe 4 80mm 4500rpms fans with like 40cfm air flow blasting right ont he bulb and then evacuating the case with some ducting would work. The problem is the with MH and all bulbs, and the reason some say hot some say it isnt. Is becasue the bulb does radiate heat. The light itself is much cooler though. Like a car headlight that is Halogen is pretty hot if you put your hand in front of it. A focused beam of MH light is much more intense and cooler. Thus not heating the panel as much per lumen it gets.🙂
brightness
I was just researching this brightness issue my self. I went to Ultimate electronics and was looking at their most expensive projector. A sharp sharpvisoin projector. It was $10000. Any ways it was 800 ANSI lumens and they had all the lights on in the room and you could see the picture just fine. Now taking into account to loss of light in a diy projector you get roughly 2%-10% of the actual light through the projecort (assuming you are not using a condencer lens and a reflector) that would be between 800 and 4000 ANSI lumens. It would be closer to 25% if you were using a reflector and condencer. In my design im using a philips 400 Watt MH bulb and a reflector and condencer. Im just waiting on my lcd and the controllers for it.
Xander
I was just researching this brightness issue my self. I went to Ultimate electronics and was looking at their most expensive projector. A sharp sharpvisoin projector. It was $10000. Any ways it was 800 ANSI lumens and they had all the lights on in the room and you could see the picture just fine. Now taking into account to loss of light in a diy projector you get roughly 2%-10% of the actual light through the projecort (assuming you are not using a condencer lens and a reflector) that would be between 800 and 4000 ANSI lumens. It would be closer to 25% if you were using a reflector and condencer. In my design im using a philips 400 Watt MH bulb and a reflector and condencer. Im just waiting on my lcd and the controllers for it.
Xander
Man only 800 Ansi, My regular projector is 700Ansi and once a cealing light is turned on it looks washed out, are you sure you didnt mean 1800? Also, excuse my ignorance I know what a reflector is but whats a condencer, is it the convex glass thats just below the mirror on a OHP? and as for a reflector I like the idea of rolled aluminup( used for houses etc) but how do you get it to be polished? Also I read that the light needs to be polarized to be able to go through the lcd, what does that exactly mean? thanks for any further info
My info
I am for certian that it was only 800ANSI. I thought they were wrong till they put the manual for the projector in my hands and it reads 800ANSI. yes the condencer is that convex lens in an OHP, it evenly spreads the light over the fresnel lens. Second i am using an actual parabolic reflector that we had just laying arround work. Luckly my Mom is a Theater lighting expert and she is a theater director so i have done this kind of stuff for a long time (i guess that is why im into diy projectors and diy audio he he he) you will get a much brighter picture if you use a prefab reflector, i had to make a custom cover to make a holder for the condencer lens on the reflecter. if you want to see some good pic of this go to www.hommie.net . I'll post pics of my PJ as soon as i get mine finished and have my screen finished. BTW what kind of lenses are you using and what is your lcd. I dont know who told you that it has to be polarized but mine isnt and so far its really really bright. I am using a laptop lcd that has a top resolution 1024x768 .
Xander Snyder
I am for certian that it was only 800ANSI. I thought they were wrong till they put the manual for the projector in my hands and it reads 800ANSI. yes the condencer is that convex lens in an OHP, it evenly spreads the light over the fresnel lens. Second i am using an actual parabolic reflector that we had just laying arround work. Luckly my Mom is a Theater lighting expert and she is a theater director so i have done this kind of stuff for a long time (i guess that is why im into diy projectors and diy audio he he he) you will get a much brighter picture if you use a prefab reflector, i had to make a custom cover to make a holder for the condencer lens on the reflecter. if you want to see some good pic of this go to www.hommie.net . I'll post pics of my PJ as soon as i get mine finished and have my screen finished. BTW what kind of lenses are you using and what is your lcd. I dont know who told you that it has to be polarized but mine isnt and so far its really really bright. I am using a laptop lcd that has a top resolution 1024x768 .
Xander Snyder
Hey I checked out that site but couldnt find a seller of prefab reflecters, I was thinking would Mylar( baloons) work for a reflective surface, or do any of you all have any Ideas for a good reflector, or how to polish alluminum sheeting. Right now My proxima 9210 Is In my basement theater, Great in the dark but with lights on not so good, So Im planning on getting a Cheap OHP and ripping everything out and puting the MH in that, So far I have heard that many have tried Just 1 MH at 400 watts and they said It led to dissapointing results. So thats why I asked about what Polarized light ment( I have no clue) Hopefully we can keep this discussion going, Oh BTW this projector would just be in my room mabe projecting a 60-70 IN picture, But I want to Not have to close the blinds( so it would be just like a reg tv) and Im gonna use a OHP projection panel. Thanks for any more input.
More info
When i dirrected you to the site i meant it to be as a refrence for what i was talking about, sorry if that seemed misleading 😱 . There a a bunch of polishing compounds that you could get at a local auto zone or orliey auto parts store. Mylar would be really good but its very expensive and hard to work with. its also very difficult to make a reflector. There is a lot of math involved with creating one (we could make an entire thread just for that). But if you know what you are doing you could make a very good reflector. The whole purpose of the reflector and condencer is to send a focused ammount of light through the fresnel and thus through the projector. There are some good ideas and examples of diy projectors on Alan's site www.diylabs.org . he has some good products for sale, lenses and other good diy pj stuff. I would really like to know who is dissapointed with a 400 watt but if you saw the pic on hommie.net you would have noticed that they are increadbly bright. Wow this is getting lengthy. What screen did you say? This is a really really good fourm, also check out www.diyprojection.com
Xander
When i dirrected you to the site i meant it to be as a refrence for what i was talking about, sorry if that seemed misleading 😱 . There a a bunch of polishing compounds that you could get at a local auto zone or orliey auto parts store. Mylar would be really good but its very expensive and hard to work with. its also very difficult to make a reflector. There is a lot of math involved with creating one (we could make an entire thread just for that). But if you know what you are doing you could make a very good reflector. The whole purpose of the reflector and condencer is to send a focused ammount of light through the fresnel and thus through the projector. There are some good ideas and examples of diy projectors on Alan's site www.diylabs.org . he has some good products for sale, lenses and other good diy pj stuff. I would really like to know who is dissapointed with a 400 watt but if you saw the pic on hommie.net you would have noticed that they are increadbly bright. Wow this is getting lengthy. What screen did you say? This is a really really good fourm, also check out www.diyprojection.com
Xander
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