Brain what do you think this distance should be?

Shown in Sketch..

Thanks, Joe

AnyOne

AnyOne

?????

Joe, there are several variables that could make that distance change. What is important is the pj lens to panel distance, as the it is the pj lens that does the focusing. If you use the collector up front then you will have one distance and if you use the collector in back you would have another. The pj lens to panel distance is static when projecting at a fixed throw.

ok, lets say that the Fresnel is infront of the LCD the distance would be about 340mm from proj. lens to lcd, but where within the PJ lens does the focal point fall? the proj. lens (triplet) is a little over 30mm.
Or does it fall infront of it?

This is kindof cridical to my new design thats why i need the distance from the rear or front of triplet. and then alow 2" focus.

The measurements in the guide are from the back of the pj lens to panel. You want the light from the collector filling the lens as much as possible.

i have 80 inches from the lense to the wall and i was woundering if that would be enough for a decent size picture

That will give you an 80" diagonal image.

ok if I'm calculating this correct, wouldn't you take the width of the LCD, and divide that into 330mm. That will tell you how many mm the image is condessing for the distance it travels, then just figure out when it is condensed to the width of the lens. Confusing I know.