Alright...I've finally started building my projector...and I've reached a point where I must admit that i think I've screwed the pooch bigtime.
Q1: What's a good technique for cleaning the rough side of a fresenel? I've tried and tried again to get each lil groove cleaned out, but the problem seems to be that whatever rag/cloth I use seems to leave more junk in the grooves than it takes out.
Q2: I'm using a standard 500w halogen work lamp for testing purposes and my picture is just so dim that it's not even funny. I am not sure if it's because my fresnel lenses are dirty, or because I don't have the proper light source. I'm reluctant to spend $150 on a good lamp at this time if I can get by with the halogen for testing purposes until after x-mas. Eventually I'll spring for it, but my question is...how bright of a picture should I expect with a 500w halogen compared to a 250 MH lamp(assuming all other factors are constant)?
Q1: What's a good technique for cleaning the rough side of a fresenel? I've tried and tried again to get each lil groove cleaned out, but the problem seems to be that whatever rag/cloth I use seems to leave more junk in the grooves than it takes out.
Q2: I'm using a standard 500w halogen work lamp for testing purposes and my picture is just so dim that it's not even funny. I am not sure if it's because my fresnel lenses are dirty, or because I don't have the proper light source. I'm reluctant to spend $150 on a good lamp at this time if I can get by with the halogen for testing purposes until after x-mas. Eventually I'll spring for it, but my question is...how bright of a picture should I expect with a 500w halogen compared to a 250 MH lamp(assuming all other factors are constant)?
ok, i'm one of the newbies but follow along with me to eliminate why..
1. Are you using a reflector to increase the light?
2. I believe fresnel lenses have a top and bottom. so try turning it around? ( i could be wrong but i marked my top and bottom fresnel from my Dukane Starfire just to make sure)
do you have the fresnel between the light source and the lcd? and do you have glass between the fresnel and lcd? (not sure if you need it but some use it i think.)
i think you need to tell us more about your setup so we can figure it out together.
1. Are you using a reflector to increase the light?
2. I believe fresnel lenses have a top and bottom. so try turning it around? ( i could be wrong but i marked my top and bottom fresnel from my Dukane Starfire just to make sure)
do you have the fresnel between the light source and the lcd? and do you have glass between the fresnel and lcd? (not sure if you need it but some use it i think.)
i think you need to tell us more about your setup so we can figure it out together.
I tried taking some pictures, but it's just too dark to really see anything. I think I noticed one source of the problem. no condenser lens. When I hold that puppy in front of the lamp, I get a very bright horizontal bar acrossed the screen...this is of course because I'm using a halogen, and the filament is a horizontal bar shape. So I think I've solved my brightness problem. I'm sure a reflector (other than the crappy one that came as part of the lamp) would help. Now to figure out a good way of cleaning these fresnels of the filth much they have aquired.
I'm also getting dark corners, but I know there are loads of posts about those, so I'll go find 'em.
😀
I'm also getting dark corners, but I know there are loads of posts about those, so I'll go find 'em.
😀
i think you're onto the condensor lens thing.
lumenlab says anything less than 400w needs one.
and or that sphere-reflector.
and a mirror at a 45 degree angle to the lcd/fresnel plane....?
lumenlab says anything less than 400w needs one.
and or that sphere-reflector.
and a mirror at a 45 degree angle to the lcd/fresnel plane....?
hmmm...I don't know if a mirror is necessary, but I'll keep an open mind on that. Just need to get this crap off the lenses. If I figure out something that works well, I'll be sure to post it.
Well my fresnels were also dirty and messy. The best way to clean them is:
Shower them with warm water in a bath-tub. Water under pressure sholud take care of all the junk in the grooves 😉 Then poure some distilled water on them to make them crystal clear and then let them dry out. Worked for me 😎
Shower them with warm water in a bath-tub. Water under pressure sholud take care of all the junk in the grooves 😉 Then poure some distilled water on them to make them crystal clear and then let them dry out. Worked for me 😎
it's about 2 degrees here right now, and half of this work I'm doing in the garage....so I can blame it on the weather if the whole thing looks 'hurried'.🙂
yeah...there's gonna be something wherever ya go though...cold, hurricanes, tornados, earthquakes...with that said...I would prefer just about any of those to the bitter cold right about now....and it's gonna get colder. It pretty much saps my will to do just about anything. 
condenser lens
hi i was reading your post about the condenser,im trying to find out what the distance from the light to the condenser should be?
can anyone help😕
hi i was reading your post about the condenser,im trying to find out what the distance from the light to the condenser should be?
can anyone help😕
well..
I'm knowingly using the wrong type of light source for now, so I may be wrong. With that said, I turned on my lamp with nothing in front of it but a sheet. Then I held the condenser in front of the lamp about 6" and slowly moved it towards the light while wtching the sheet. Once the light exploded into a much brighter and cleaner light that covered most of the sheet, I stopped. I have it about 1-2" from the lamp, but nothing is finalized. I'm more of a trial and error type, so maybe someone on here can give you a more scientific answer.
I'm knowingly using the wrong type of light source for now, so I may be wrong. With that said, I turned on my lamp with nothing in front of it but a sheet. Then I held the condenser in front of the lamp about 6" and slowly moved it towards the light while wtching the sheet. Once the light exploded into a much brighter and cleaner light that covered most of the sheet, I stopped. I have it about 1-2" from the lamp, but nothing is finalized. I'm more of a trial and error type, so maybe someone on here can give you a more scientific answer.
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