I saw this "Charles Beseler 14" E F S-III Photo Enlargement Lense" on Ebay, and wondered if it could be used as a projection lens. 14 inches is about 355mm. What kind of problems can I expect to see trying to pair it with a 330mm front (field) fresnel?

Assuming it even is a triplet, might this be an ideal lens for a 17" non-Pro build?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...em=220036918090

Well, either way, I bought it. So I guess we'll find out soon enough.

triplet will need to be 400mm+ from the LCD.. out of reach of the 330mm. maybe you can get your hands on a 450 or 500mm fressy.

Could I do a sort of Elken-style mod to it and make it a shorter FL? Would that allow me to use it?

The 14" triplet is fine for a 330mm front fresnel. All triplets focus longer than the stated amount.

The FOV of the 14" triplet will be smaller than a reg 80mm triplet so you may get a soft focus on a 15" LCD. It is not good for a 17" LCD at all. I would guess that the work plate it is made to focus on is 8"x8"

It is a low "F"" lens so a longer arc lamp will work fine with it.

A HQI 400 and a 6x9 condenser and a 15" LCD would be a nice setup or the T15 lamp and a 6x9 condenser and a 15" LCD.

This lens is a lot better for brightness than the standard triplet but may give softer focus on the edge of the screen even with a 15" LCD.

well if thats the case I retract my comment

Okay, thanks AV.

So you're saying that the FOV of this lens is less than that of my standard LL triplet? I have much more to learn; I assumed that this wider triplet would be able to "see" more of my LCD.

How do we estimate FOV of a triplet?

In any case, I'll have fun playing with this lens.

I did a plog long time ago call "the fov test” but it is more accurate to use a test setup and a LCD or transparencies.

http://www.lumenlab.com/forums/index.php?s...ost&p=94889

You are actually correct, the fresnel should be 380-400mm. But a 330mm can be made to work, just not as efficient as the longer fresnel.

DJ