ducktv
Aug 12 2005, 07:44 AM
Ok heres the problem. (sorry no pics of the problem). I have my lens set up in my sled all measurements are correct, Now what I have done before putting in my lcd was use one of those overhead pj transparencies that you write on to check for focus. Now when I put it in the slot for the lcd I cant get it to focus, but if I move it behind all the lenses and even behind the lexan, I mean about 4 to 5 inches behind I get it to focus. Don't know whats going on. I'm wondering if LL sent me the pro lens kit although I'm using a 15 inch monitor. Anyone have any ideas???
GadgetSmith
Aug 12 2005, 12:50 PM
Focus has little to do with the fresnel lenses as long as you keep them at the distances specified in the guide. 15mm from collimator to LCD, and 20mm from LCD to field fresnel. If you are not getting focus it is most likely due to the triplet to LCD distance (this is what determines focus). You will need to move your triplet either towards or away from the LCD in order to focus. Try it and see what you get.
SupraGuy
Aug 12 2005, 03:59 PM
What is the distance between the "LCD" and the projection lens? And the distance between the projection lens and the "screen"?
Remember at the focal distance, the picture is focused on infinity. This may be okay if you're projecting onto clouds on an overcast night, but it's not going to work on a screen that's 10' away. Everything will be blurry, with the smallest detail possible to resolve being the size of the lens.
If the screen is 3' away, then the lens needs to be over 2' from the "LCD" The closer the screen, the further the projection lens has to be from the image source. This is the way that focus works.
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