im thinking about using a precondensor lens but im not sure about the dimensions that is required for my setup.
im using a 220mm/330mm fresnels, and a 60mm(clear aperture) 317fl triplet and a 15.6" Lcd panel.i tried using the precondensor calculator and here is what i get
Pre-condenser
(n-1)*fl =Radius= 78.447 mm
Marginal BFL= 116.9888949 mm
Marginal Ray Angle = 25.61106551 deg

do these numbers look right?
if not please let me know the correct dimensions.