psone with 50mm diameter objective?

[dracul]

I was wondering if I can get away with using a 50mm diameter projection lens such as this one using the psone size screen which is 4 inches wide?
http://www.surplusshed.com/pages/item/l2095.html

or this one:

http://www.surplusshed.com/pages/item/l3297.html

 

[dracul]

so using a 13 inch FL fresnel there is no way i can use a 7.5 inch FL objective is there?

 

[dracul]

Anyone. Will this lens work with a psone and a standard unsplit OHP fresnel

 

[Guy Grotke]

sure

USing a 7.5" lens with a 13" fresnel you would get a very dim image, since the light would form a spot larger than the projection lens.

But you can get a 200 mm fl fresnel that would work fine with a 170 mm fl projection lens.

If you have an unsplit OHP fresnel pair, the fresnel on the lamp side is probably 200 mm fl and the fresnel on the projection lens side is probably 330 mm fl. If you flip it the other way, the arc image from a lamp 330 mm away would be focussed 200 mm on the other side. That would work well with a 170 mm lens.