I don't really understand what the LL guide means when they talk about the focal point between the lcd and the lens. what does this have to do with? does this mean you have to place the lcd at a special point depending on how big of a image you want projected? and is there a way to make it very versatile. thx sorry im a nub when it comes to optics (but the wiring and carpentry will be a piece of cake)

Thx in advance
-Nick

It's the distance that you need to have the lens away from the LCD in order to get
a focused projection from it. Your projection lens, however, does move in order to
focus on a point closer or further away from what the throw of that lens is.

So basically, it's your PJ lens' starting point distance from the LCD. Hope that helps.

nono, its the distance between your focing lense (triplet) and the virtual image of your LCD, not the actual LCD panel. download the focal calc program here http://www.lumenlab.com/forums/index.php?showtopic=7912
this will tell you the distance between your LCD and your triplet. notice for example, with a 17" LCD and 500mm triplet, distance between the two is 580-600mm, not 500mm.

Thx alot guys I just have one last question what does the focal calc mean by split and un-split does that have to do with putting glass on either side of the lcd?

Split is one fresnel on each side of the lcd, and unsplit is both fresnels on the lamp side of the lcd.

if you don't need keystoning (i.e., your projector will be at the same level as the middle of your projection, not on the floor, or ceiling) then it is highly recommended that you use an unsplit design for the noticeable increase in PQ.

If you really look at the focal calculator, it shows the distance of the LCD
from the middle of the triplet, and triplet FL is calculated from the rear
lens of the triplet, isn't it?

That's been tossed around a bit. I think it's from the lens "EFL" or something like that which may be safely assumed to be at the geometric center of the lens. A little adjustability is a must as far as distance between lens (whichever point you choose to use as reference) and LCD. That's my understanding. Hope that helps and doesn't simply confuse the issue. (I've got a chronic case of confusion and it's highly contagious!)