I have a JVC HD100 with stock lens. Last year the focus ring became tight as a I got toward infinity. It still works, but its much looser at the the closer range. Someone told me I could ship it to JVC to repair it, but I think that would take too much time. Has anyone had this problem before?

The 16x fujinon on my JVC HD110 has a plastic frony barrel. If I clamp a mattebox onto the front ring, it distorts enough to bind. It is necessary to have a metal ring screwed into the plastic barrel to mitigate distortions when using a mattebox.

I think you're right Bill. I looked at my lens barrel and it looks a little distorted. Do they make metal rings to fit over it or is this something you made?

-Clay

buy one of those metal filter adapter rings to screw into the front of the plastic

Century makes a ring for the JVC 16x lens to stiffen the barrel when adding a century wide angle adapter:
CENTURY 82MM 100U RING - Schneider Optics (http://www.schneideroptics.com/Ecommerce/CatalogItemDetail.aspx?CID=1084&IID=5874)

However, a UV filter (preferably one with a thicker edge to give more support) or an adapter ring as Bill suggests is cheaper.