lense order


2005-07-03 3:59 pm
What order and direction do i put the lenses, like, i have
the 200ish and the 300ish fresnel and the triplet (2+1 kit)

what order do i put the fresnel's and which direction do the ridges face? i'm building the mach3 with a 14" lcd, a 250watt mogul base lamp, Thats the other question, i could only get the frosted lamp (not the clear one) becasue thats what came wtih the fitting and i'd like to use that for now,. what difference will i get using this one instead of a clear? those lamps are hell bright.

jsut got to work out spacing (any pointers) and placement of the lenses, buy a new mirror (shattered the last one) and join one of the boards to the panel. everything else is good to go.

Thanks people, this is my first posting (though not my first read :)



2004-04-07 7:23 pm
Good question...
In this order i have the bulb - 220mm - lcd - 330mm - lens

so that's from center of the bulb to first lens is 220mm then 15mm to the lcd them from the lcd 20mm to the second lens then 330mm to the objective lens.
These are my lens sizes...yours might be a little different



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Put the 200ish fresnel about 200 mm from the lamp arc. Then 20 mm to the LCD. Then 20 mm more to the 300ish fresnel. Then play with the projection lens distance until you get a focussed image on the screen. The fresnel ridges have to face the other fresnel's ridges. So in this split design, they will both face the LCD.

Or you can try a non-split design: Both fresnels together 20 mm before the LCD, 200ish on the lamp side, 300ish on the LCD side.

Once you get a screen image focussed, you can fiddle a bit with the lamp to fresnel spacing to see if you get a brighter and more even image.