Ok, i'm new, and currently working on building my own box. (a light-weight one) and ran into a small problem with google sketch-up.. I have no idea what the projection angle is. Or whatever you would call it. The image being projection out the lens. Onto say.. 80"w x 60"h, Here is a picture of what I did, not sure if that would be right (with 12% keystone)


Any help at all would be great, I looked around but got lost as far as knowing where to find that info.


EDIT: The PJ lens would be about 81-86" from the center of the screen.. (Not sure what info will help, but guess that would)

If you have 12% keystoning, that would be like 90*0.12=10.8 degrees projection angle? If my calculations are correct?
Or if you measure the exact distance of the lens throw (81-86") and the horizontal line from the projection lens to the wall, and then use cos((distance to wall)/(throw distance)) you would also get it me thinks.
I'm mostly likely wrong on the calculation though, since I haven't been using math for years. Please correct me.

But.. If you make the front fresnel swing freely, it will adjust automatically to the correct keystone angle. Which I guess is what you're looking for, right?

Also, perhaps the focal calculator can be of some help, if you don't have it already.