I have asked this question several times and never got a responce. I have a
kinderman 6X6 projector and have wondered if the lens it came with, a
Will-Wetzlar Maginon f3.0 150mm lens is good, bad or indifferent. Well I
noticed on german ebay foto-walser has been selling Rollei hediosmat f2.8
150mm projector lenses (the good made in germany ones) for dirt cheap. I
bought one and spend a couple of hours tonight hacking up a mount onto the
front of my kinderman projector to try it out.

Well now I can answer the question about the Will-Wetzlar lens, it's a piece
of crap! The rollei lens is SO much better it isn't even funny. Before my
6x6 slides didn't look any better than my 35mm ones (projected with a kodak
projector and a raynox 100mm f2.8 lens) if even as good. Now they look
incredible! If anyone has one of these projectors, grab one of those rollei
lenses (I paid like $60 shipped) and throw it on your projector!

I'm going to make a short page showing how to mount these later next week,
this project is WELL worth it!