Hi All,

Using the LL optics how can I control the projected image size and focus?

I would not like to move the whole projector to change the size of the projected image.

Thanks,

the fixed triplet does not allow you to zoom in/out on the image. You need a varifocal for that purppose.

By now the only practical solution you have is moving the field frensell 1-2cm farther form the LCD (not tilting, paralell separation), so the fresnell will magnify your 15" lcd so will the image as well. But you will notice farther the field fresnell is, more distortions will be introduced to the image. Try yourself.

Does any one know what kind of lenses to use to get the zoom effect.

You need varifocal lenses. They are NOT offered on LL. If you find some that will work, please let us know since no-one here has found any yet.

Zooming an image of a large panel more than a little bit is not practical because the length of the barrel of such a lens will not have sufficient field of view unless it is huge.

A vari-focal projection lens is not a zoom lens, its like the name states, a variable focus, takes the place from a moving triplet.

Joe