The Schneider Radionar lens is a triplet. Best performance is obtained by stopping down to at least f:8. These are a quite old design. If yours is not coated, a lens hood is strongly recommended. A dual format, 6X6 and 6X9 camera will, or should, have a mask at the film plane for using the 6X6 format. Some are permanently affixed (folding or sliding) and some are a removable mask that usually winds up getting lost. If you don't have the mask, you're limited to using the 6X9 format. Don't get mixed up and use the wrong window. I can tell you what that does. Hope you enjoy your camera. Old folders are a lot of fun.