Most camera models show the filter diameter on the object lens surround, as shown below.
If you can't find any writing on the lens surround, check your camera's manual to see which size of filter your camera takes. Since the PF products have filter threads you can easily screw a PF into the camera's lens. The threads are standardized to be compatible with all types of manufactured cameras. The PF products have female thread as well as male thread as shown above. Therefore you can easily screw a telephoto lens or wide angle lens into PF filter.