Hoya Multivision Glass filters are available in five types: 3PF, 3F, 5F, 6F, and 6PF. This "prism" type filter is generally used to create fantasy images. The multiple images appear to "revolve" around a central image. The number of images created is determined by the grade of filter purchased (i.e. 3F, 5F, 6F, etc). The effect is strongest with a relatively dark background and at larger apertures.
"F" models create a triangle around which float the same image. "PF" models are linear in structure creating a horizontal flow of the same image.
Note! The multi-images appear closer together with wide-angle lenses and farther apart with telephoto lenses