I don't know if this will help, but I have a Perkeo II, and by chance tried one of the three stepping rings from a Century Optics wide angle adapter on it. The stepping ring fit, and fits tightly enough against the lens for me to be able to close the camera without taking it off. Now I just use screw on filters (49mm) and while I'm careful to support the lens and struts, there is no real force placed on those parts of the camera. I just gently screw filters and/or the wide angle adapter onto the stepping ring. It works very well, and now I can get the equivalent of a 55mm lens when I use the WA adapter with little or no vignetting, depending on the aperature I use. Century Optics adapters are especially attractive, because they transmit light so well, there is essentially no loss of exposure. Most adapters, both tele and wide cost you a stop or two of light. If you measure the lens diameter, maybe you can find a stepping ring to fit, you'll be set. I'm at work, and don't have the camera with me, but I'll check when I get home. I believe its a 29 or 30.5mm diameter.