| blurry over here, sharp over there... - Click HERE for Original Thread |
| alphadog808 |
Hey guys,
I just retrofitted my OHP with a Metal Halide from DIYlabs. First, I have to say the color is markedly improved...
I also noticed that it seems now that the top half of my image is a bit darker and more blurry than the bottom half of the image.
I'm wondering what could be causing this? I see the problem when I use the condenser or not.
Also, I'm wondering if it's just maybe cause I'm sitting too close to the screen. I currently have a 52"x72" image and I'm sitting maybe....7 feet away. If I go real far back, around 12 feet or more, it's harder to notice the blurriness. In fact, the farther back the better!
I'm wondering if maybe my light isn't being aimed right at the fresnel? |
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| cruser |
| it sound to me like your bulb is off center |
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| alphadog808 |
Yah, that's what I'd guess too...BUT is it too much to the left, or the right? Or too slanted too much forward? Back? To be more clear, my OHP has a mirror inside so I have to angle the bulb to fire at the glass then straight up.
From my nonintelligent point of view, I'd guess that the bulb is pointing too much down...as the light will hit the front part of the triplet lens(if you were looking up to the lens). But what do I know?
I wonder tho...what if I took the mirror out and tried to fire the light straight up from the bottom? The fresnel is not expecting that short a light length, so what would happen to the picture? |
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| cruser |
| your lamp would be out of the fresnel's focal length and would not light up the entire stage |
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| cruser |
| 1 way you could find out wich way to move the lamp is to insert a piece of paper into the light path infront of the lamp watch it on the screen then move the lamp acrodingly |
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| ace3000_1 |
I agree with cruser, its either that or the projection lens is off center.
Trev |
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