I sent basically the same message to the forum at diyprojectorcompany.com (thats where the theory is coming from) but I am trying to cast as wide a net as possible.

This is my first post to this group. I have looked at a lot of messages and read thru the theory section on the website and have a few questions on what is the best lens to use for the following setup.

Source image-3by5" - 5.8" diag

Projected image = 6by10' or 72by120" - 139.9" diag

Distance to screen is 20' or 240"

This is a magnification of 24x

Rearranging the equations in the theory to solve for focal length with the above numbers I get a focal length of 9.5" or 242.5mm. Does this sound right to y'all?

With this setup what would be the best focal length fresnal lens to use and why?

I've read the theory section but one thing that confuses me is where do you place the projection lens in relation to the image? Do you place the image at the focal point of the projection lens?

Any help you guys can give me would be greatly appreciated.

Thanks,