Moire Fresnel Lense Diamond artifacts

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I'm currenlty using the 10"X10" fresnel taken an OHP which gives quite good results but isnt big enough to capture the whole 15" LCD image. I've purchased the fresnel lense setup from lumen lab and get a good picture in the middle (somewhat better than before, but not much), but get these diamond shaped artifacts showing up towards the edges. I've tried varying the spacing, and different split configurations but couldnt resolve the problem.

Any thoughts?? The image shows these diamond shapes all over the sides that are about 6-10 pixels tall (1024 res). Where should I focus my efforts - do the Moire effects become more obvious from the 2 overlaying ring patterns, or just from the LCD overlaying the horizontal and vertical lines over the rings? Or in other words - Tonight when I remove the LCD screen and put in some transparent paper I test with would I still see the Moire effect??

DJM
 
well i did finally get something which is acceptable. Overall the focus is much better than before, but the moire effect is still there - I added some spacing between the lcd and each fresnel and can reduce the effect but not eliminate it. From the casual observer I don't think it would be a problem but obviously those of us who spend a good deal of time on playing with such things tend to over notice the samll things.

Actually at a certain spacing the moire effect does seem to break up the screen door effect but its not the same from center to edge (more on outside than in due to the angle change per distance).
 
Maybe a picture or something would help, I can't really visualize what your describing. If you mean the rings that appear from the fresnels then they could be out of alignment with each-other. Or, more likely is that the lcd is just too close and the projection lens is focusing on the fresnels. A good distance is around 20mm between the fresnels and the lcd.
 
If you take the rings, and superimpose the vertical lines from the LCD screen door you get diamonds - see the pic - the goal is to get the focus on the LCD and not the "system" of the three components
 

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