Got some issues with my light, I think I have placed the fresnel to far from the lamp, or too close.

Im getting some brownish color in the edges of the screen (no, not overheating the LCD, I only get 86F). Wondering what to do?

Posting some images, hopefully they will help some?

Yes, those certainly are issues...

First off, verify that your 220 and 317mm fresnels are in the correct placement, and orientation. (The grooved sides should point towards each other.)

Next, we should see a picture of the inside of the projector, specifically of hte triplet area while the light is on. This looks like a case of the light not hitting the triplet, to me. This is, of course, made worse when the fresnel lenses are not in the correct orientation.

Oo, well its a OHP system, so its only 1 fresnel >_<

I will check some more tomorrow, I am guessing I got the back fresnel wrong, I might have skewed it 0,5mm on one side when I screwed in some holders for the plate.

Took a quick picture, and I think it is hitting the triplet a bit high.



Gonna redo the fresnelmount tomorrow.

You need to adjust your lamp position relative to the fresnel.

The light will center on a line that connects the center of the fresnels with the lamp. It looks as though this line is not centered correctly.

Also, there is signifigant loss of light around the triplet. This can also be fixed by adjusting hte lamp position relative to the fresnel. It will be better if the lamp is either further or closer to the fresnel.

Allright! I will try that.


Thanks for the help!

What bulb are you using it looks like the color temp maybe too hot as you don't appear to be getting the blues in the images too well.

The bulb is a Osram XENOPHOT HLX 36v 400w, I know it sucks a little on colors, but I guess I will try to correct it with color temp on the LCD (I had it red during the pictures btw.)


edit: Oh, if someone knows a better bulb that runs on 36v and the same socket, let me know! Me want to buy.

Fixed a little, it seems my fresnel was to far away, also my LCD panel was a bit twisted.

Edit: By the way, im projecting at a poor quality painted wall, so im mostly tweaking the light at this point.

SupraGuy,
Will the triplet function the same when mounted backwards?

Haas: I don't know, but I don't think so. I would expect some spherical abberation, and possibly some chromatic abberation as well if the triplet were reversed.

Frakk: Speaking of spherical abberation, there seems to be some with your projection. The top and bottom of your image appears to be bowed outwards. The lighting looks much better, though.

I just put those images up on my wall, and I have to say that I just sat there and stared for a while. The cyan haired girl image seems to really show off the projector, more so than any single image that I've tried projecting so far. Though it does show that my fresnel frame gets slightly in the way on one corner, jus enough to remove one of the edge grid lines. The strawberries also look good, but that image is too simple to really show off the projector's quality.

Oh, and displaying the grayscale image, metering in the center of each of the 9 white spots, I came up with a total of 258 ANSI lumens. This is at the lower end of what a commercial projector should produce, but higher than I'd measured before (I think I had the meter closer to the edges/corners for the outer 8 measurements.)

frakk which fresnel was too far away from what?

just curious as I am in teh process of tweaking now, while I dont have similar problems every bit of knowledge helps

I moved the back fresnel further back, also corrected the LCD panel (had skewed itself by 0,5mm back on one side).

I get very fuzzy sides on it now tough, since I moved the fresnel further away from the LCD panel. I might have to unscrew the whole thing, and mount it again, (I have just fixed the fresnel with ducttape for now, I am guessing I need to adjust it even more anyways.

I could try to switch the triplet, (the other way around), to see if this fixes anything?