Hey
I'm wondering how the 250 W Double Ended MH from diylabs.org is going to provide sufficent lumens to have a picture during the day? If 400 watt MH only provides 400 ANSI lumens how is a 250 w MH going to produce more? Does anyone know how many lumens the double ended 250 w produces?
I'm wondering how the 250 W Double Ended MH from diylabs.org is going to provide sufficent lumens to have a picture during the day? If 400 watt MH only provides 400 ANSI lumens how is a 250 w MH going to produce more? Does anyone know how many lumens the double ended 250 w produces?
mikekniner said:
where did you see/hear that a 400 watt delivers 400 ANSI lumens? becuause that is far form the truth
and the 250 watt HQI is start 20,000 lumens 16,000 lumens mean.
Well on my projector it produces 400 ANSI lumens. I believe around 36000 mean. But I don't understand is how can that 250 W HQI supposudly bring better results than my 400W MH?
Im assuming your talking about a smaller 400watt bulb than diy labs is supplying, like the one that is intended for your overhead? and if so im pretty sure that its not 36000 mean lumens. Im hoping a double ended metal halide will put out more than 400 ansi because its what i plan to retrofit into my commercial projector. Do you know where you got the fact of your mean lumens?
mikekniner said:
what kind of 400W MH do you have? is it double ended too?
how do you know the one in your projector produces 400 Lm?
Effficiency
It has to due with how efficient your design is. In most systems using a double ended lamp, a condensor lens is used plus a spherical reflector. Also, the double ended lamps are a lot closer to a pinpoint source. The larger metal halide lamps are a brute force method (even with a good reflector), since they are NOT a point source you are loosing a large percentage of the light they produce. That is why some people are not satisfied with the 400W MH and are considering moving to 1000W !!!!! Efficiency is better than power. Just look at Ywh's results.
It has to due with how efficient your design is. In most systems using a double ended lamp, a condensor lens is used plus a spherical reflector. Also, the double ended lamps are a lot closer to a pinpoint source. The larger metal halide lamps are a brute force method (even with a good reflector), since they are NOT a point source you are loosing a large percentage of the light they produce. That is why some people are not satisfied with the 400W MH and are considering moving to 1000W !!!!! Efficiency is better than power. Just look at Ywh's results.
thank you babybyter great explanation i couldnt of said it better my self! 🙂
and pooh, i think an HQi would be MORE than good for you projector.retail projectors use smaller lcds, and small lcds dont need 400-250 watt systems, i've seen many that use 100 w, some less soem more.
and pooh, i think an HQi would be MORE than good for you projector.retail projectors use smaller lcds, and small lcds dont need 400-250 watt systems, i've seen many that use 100 w, some less soem more.
HAHA you called him babybyter, yeah im hopping it will give me better results than the actual 400ish dollar bulb that is supposed to be in it, if i do it right of course. I CANT WAIT, god it better not be a doa..
daytime viewing
My 575w double ended MH bulb in my Elmo 305SD powered projector is not suitable for daytime viewing....maybe OK with a small lamp on in the room at night, but that's it. I'd like to see how well a $3-$5K DLP does in the daytime for comparison.....I don't believe ANY front projection setup will give great daytime viewing. (say with blinds open)
For that you need a rear projection setup. I tried that route ....but w/o a fresnel/lenticular/blackstripe screen (like in my Phillips 50" RPTV) you will not get good brightness or even edge to edge lighting. (been there, done that)
So that leaves us with front projection.....
and we know that we only get about 10% of our bulbs light to the screen. Using a lightmeter I've found that putting the upper fresnel on top of the lcd definitely evens out the brightness across the screen, but it is still brighter in the center. But this isn't noticible watching movies.
So now my only concern is to try to recycle wasted light and get it through the lcd to brighten the image. If you've seen my screenshots you know my picture is pretty good...but it's still nowhere near as bright as my RPTV. I just got a sample of the 1/4 wave retarder film, and am waiting on the reflective polarizer film to do more "experiments". MOOOOAHAHAHAHA....
Will keep you posted...and anyone else experimenting with "light recycling", please speak up.
My 575w double ended MH bulb in my Elmo 305SD powered projector is not suitable for daytime viewing....maybe OK with a small lamp on in the room at night, but that's it. I'd like to see how well a $3-$5K DLP does in the daytime for comparison.....I don't believe ANY front projection setup will give great daytime viewing. (say with blinds open)
For that you need a rear projection setup. I tried that route ....but w/o a fresnel/lenticular/blackstripe screen (like in my Phillips 50" RPTV) you will not get good brightness or even edge to edge lighting. (been there, done that)
So that leaves us with front projection.....
and we know that we only get about 10% of our bulbs light to the screen. Using a lightmeter I've found that putting the upper fresnel on top of the lcd definitely evens out the brightness across the screen, but it is still brighter in the center. But this isn't noticible watching movies.
So now my only concern is to try to recycle wasted light and get it through the lcd to brighten the image. If you've seen my screenshots you know my picture is pretty good...but it's still nowhere near as bright as my RPTV. I just got a sample of the 1/4 wave retarder film, and am waiting on the reflective polarizer film to do more "experiments". MOOOOAHAHAHAHA....
Will keep you posted...and anyone else experimenting with "light recycling", please speak up.
Proto5...
I have tried the various films from 3M and really didn't notice a change. I think it only really works in laptiop setups. That is with a light guide with a mirror like surface behind it to send the recycled light back through the light guide and then back through the polarization film at the right angel. Without that exact setup the films don't really do much.
I have tried the various films from 3M and really didn't notice a change. I think it only really works in laptiop setups. That is with a light guide with a mirror like surface behind it to send the recycled light back through the light guide and then back through the polarization film at the right angel. Without that exact setup the films don't really do much.
light recycling
Byter:
I plan on doing it right.....repolarizing the wasted light- mirror behind bulb. etc......
You don't have any "reflective polarizing film" do you?
Still waiting on that....
Byter:
I plan on doing it right.....repolarizing the wasted light- mirror behind bulb. etc......
You don't have any "reflective polarizing film" do you?
Still waiting on that....
I Think so...
but I might have throwen out the information package which came with the films. I'll check when I get home tonight.
but I might have throwen out the information package which came with the films. I'll check when I get home tonight.
I agree its all about efficiency here.....face it, no projector is really good with a bright room. Even the professional jobs arent that efficient. It all comes down to producing a proper reflector.
That said...the bigger panels we use (15 inchers) means we need more light to properly do it....just think 40000 lumens hitting a surface thats 5 inches in diameter will have less parisitic losses in the LCD material than the same amount of light hitting a 15 inch diagonal screen.....and the only way to overcome that (besides efficiency) is to go with a brighter light or a smaller LCD.
That said...the bigger panels we use (15 inchers) means we need more light to properly do it....just think 40000 lumens hitting a surface thats 5 inches in diameter will have less parisitic losses in the LCD material than the same amount of light hitting a 15 inch diagonal screen.....and the only way to overcome that (besides efficiency) is to go with a brighter light or a smaller LCD.
films
Byter-
Thanks.
Do you remember...was the reflective polarizer kind of "mirrored" on one side or what?
Byter-
Thanks.
Do you remember...was the reflective polarizer kind of "mirrored" on one side or what?
So basically if you have good optics you will get a good image right? I currently have the Mark 1 design for my projector. I have a reflector on my MH though. Than it goes through the Fresnal lens which is about 12-14 inch's from the MH, the Lcd panel is about 1 inch above the fresnal. Than I have my mirror and triplet lens. Can I go more efficent that this, if so how?
mikekninrt
You could add a condensor lens at the focal point of your reflector before your fresnel lens. This concentrates most of the reflected light from your reflector onto the fresnel. However, as I stated before, a point source meta halide light is a much better source of light than a larger MH bulb. The smaller the arc gap the better.
You could add a condensor lens at the focal point of your reflector before your fresnel lens. This concentrates most of the reflected light from your reflector onto the fresnel. However, as I stated before, a point source meta halide light is a much better source of light than a larger MH bulb. The smaller the arc gap the better.
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