Hey, I have a standard 15 inch projector. If I wanted like another 2 or 3 feet of throw with the same image size, could I get like just a little bit longer fresnel from 3dlens?

Thanks

Im not the best person to answer but i am the first !...I guess you have looked at the various calculators for focal distances available in the forum by DAZZLA et al.

http://www.lumenlab.com/forums/index.php?showforum=43

With the DIY projector you are restricted as to the distance between the Screen and position of the projector.

My own issue is my rooms too long ! I end up with having to use a 22"FL lens for a 160" screen image (if I want the projector behind me ..which Id have to)...this screensize is way too big for me! So I will probably have to build a DIY RPTV.

Throw distance is detirmined by the triplet not the fresnel, the fresnel is there to direct the light towards the triplet to increase brightness and needs to have a FL shorter than the triplet as it is already inside the distance between the LCD and triplet and we don't want it to focus inside the triplet but rather fill the triplet. Only way to increase throw (smaller projected image or projector further back) is to use a longer FL triplet search ebay for a OHP triplet of 360-400mm.