OK this would normally not be so difficult but in this case, it is.
I have a household camera - Canon Zr500. Picked it up cause it was the only small camcorder I could find with an external mic port.
I also have a Raynox HD-5000Pro wide angle lens. It comes with a bunch of adapter rings and it fit on several previous home camcorders I had before this except for my current Zr500.
You would think Canon would know what the lens size is but noone there could tell me what the lens size is.