Hmmm I wasn't sure where to post this but anyway...

Just quickly looking around for alternative keystone correction methods I stumbled apon this company

http://www.siliconoptix.com/products/Realta.cfm

Seems fairly interesting but I expect it still won't beat physical keystone correction.

I've also found a video of a commercial projector with a lens shift control.

http://www.youtube.com/watch?v=w_R6aM3_pWQ

How does this work ?
What are the con's of using this method ?
So could I use this on my triplet and it correct my keystone better than angling the Fresnels ?

Oh I also found this good definition of keystoning for anyone that might need it : http://www.theprojectorpros.com/learn-s-le..._correction.htm

That's very interesting. But in the video you have posted, they are talking about making a low quality to a high quality. They don't tell anything about keystoning right?

Grtz, Keires

How about removing the need to keystone:

http://www.lumenlab.com/forums/index.php?showtopic=23412