Help!
My projector is almost ready to go, I have everything installed except for the lcd (I ran into some ffc problems), and now when I go to do a test my projector projects a circle instead of filling out the full wide screen! There is a little light in the corners and enough light to define the 16:9 but not what it should be. I cant figure out what I did wrong or what I need to change. I used the focal length calc to set up distances between lenses but it seems to be very off still. Has anyone else had this problem? Any help would be great!
Thanks
-Tim
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Full Version: Help! Projector projects circle!
for starters what lenses and triplet are you using? What are your distances? I only had something like that when I had NO Fresnel lenses in there.
That definitely looks like improperly placed fresnels.
1. The collimator fresnel should be approximately it's FL away fromt he lamp. The grooves should face away from the lamp.
2. The collector fresnel should have the grooves facing the lamp (Or, facing th grooves on the collimator fresnel, more accurately.)
3. The fresnels and lamp position should be placed to focus the light in as small an area as possible. Any light that does not hit the triplet does not get projected.
1. The collimator fresnel should be approximately it's FL away fromt he lamp. The grooves should face away from the lamp.
2. The collector fresnel should have the grooves facing the lamp (Or, facing th grooves on the collimator fresnel, more accurately.)
3. The fresnels and lamp position should be placed to focus the light in as small an area as possible. Any light that does not hit the triplet does not get projected.
QUOTE (SupraGuy @ Jul 3 2009, 09:32 AM) 
That definitely looks like improperly placed fresnels.
1. The collimator fresnel should be approximately it's FL away fromt he lamp. The grooves should face away from the lamp.
2. The collector fresnel should have the grooves facing the lamp (Or, facing th grooves on the collimator fresnel, more accurately.)
3. The fresnels and lamp position should be placed to focus the light in as small an area as possible. Any light that does not hit the triplet does not get projected.
1. The collimator fresnel should be approximately it's FL away fromt he lamp. The grooves should face away from the lamp.
2. The collector fresnel should have the grooves facing the lamp (Or, facing th grooves on the collimator fresnel, more accurately.)
3. The fresnels and lamp position should be placed to focus the light in as small an area as possible. Any light that does not hit the triplet does not get projected.
Hmm ya im not sure what could be wrong. The collimator lens is almost exactly 220mm (its focal length) away from the lamp. The grooves on both the lenses are facing in towards eachother, and Im currently using the lumenlab pro reflector which is situated right behind my lamp. Im almost wondering if the collector lens I ordered back a year ago when I when I started everything was the wrong one. I cant see what else it could possibly be. Could that possibly be the problem? Like maybe my lens is the 317mm instead of the 650mm which its supposed to be. Or maybe the collimator lens is wrong?
I just dont know what else could cause such a drastic problem.
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Step 1. Turn on the lamp.
Step 2. Look at the light at the very front of the projector. You SHOULD see something that looks like a reversed image of the lamp. This is if things are at an appropriate distance, and your fresnels are properly collecting the light.
You may need to adjust the lamp position, the fresnel position, or both in order to get this to work.
Step 2. Look at the light at the very front of the projector. You SHOULD see something that looks like a reversed image of the lamp. This is if things are at an appropriate distance, and your fresnels are properly collecting the light.
You may need to adjust the lamp position, the fresnel position, or both in order to get this to work.
If you're using a 650mm front fresnel, then you're most likely using a 500mm triplet. Have you tried turning your triplet around?
http://www.lumenlab.com/forums/index.php?showtopic=20820
http://www.lumenlab.com/forums/index.php?s...st&p=300858
http://www.lumenlab.com/forums/index.php?showtopic=20820
http://www.lumenlab.com/forums/index.php?s...st&p=300858
Do you have a fresnel backwards?
Swap the fresnels.
Before you swap anything, check that you have things in correctly, and that the shorter FL fresnel is the one being used as the collimator, and the longer is the collector.
Then, check as I outlined above. If you're getting a large square of light, only part of which hits the triplet, then that's the biggest problem right there, and what you'll have to take care of.
By the way, in the circle that gets projected, can you see an image on the LCD? Is it in focus?
Then, check as I outlined above. If you're getting a large square of light, only part of which hits the triplet, then that's the biggest problem right there, and what you'll have to take care of.
By the way, in the circle that gets projected, can you see an image on the LCD? Is it in focus?
QUOTE (SupraGuy @ Jul 9 2009, 10:50 AM)
Before you swap anything, check that you have things in correctly, and that the shorter FL fresnel is the one being used as the collimator, and the longer is the collector.
Yeah...that's what I said, only more succinctly.
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