Lens?

Looking through the Projector guide and through various PLOGs, your Collector fresnel needs to be matched to the triplet projector lens (correct?)
What is the margin for error for this and what are the issues associated with not having it exactly matched?
I have a 342mm FL Triplet and 3DLens sells the fresnels I need, but the closest they have is 330mm (My collimator will be 220mm).

My plan is to use a bog standard 15" LCD (XGA) Monitor, if this makes any difference.

I just want to be sure before I order these, they need to come a Long way (I live in the UK, if anyone knows any UK based fresnel dealers please do tell! - Taking too long for an old OHP Unsplit to show up on ebay =()

Many thanks for any clarification, I've been scouring the board for the past 3 days pondering the design of my projector, Driving me mad

Well, it TENDS to work better when the triplet FL and fresnel FL are closely matched, but that's not a requirement by any stretch of the imagination. For example, the pro lens kit came with a 500mm triplet, and 650mm collector.

What you NEED is to have the fresnel bring the light to it's sharpest focus at the entrance to the triplet, and in order to do that most efficiently, it works best to have the FLs roughly the same.

To have them EXACTLY the same would be ideal fom a keystone correction perspective, particularly for gravity-adjusted systems.

I see!, thanks for the clarification!
Makes me wish I had a clue about optics... Electronics, Programming and music are my thing... Closest I come to Optics is the glasses I wear hah!

I think I've now got a solid design coming together! - All thanks to this forum, so many knowledgable helpful people
To sketchup Now I think!

Many thanks!