Vivitar 6-element lens?

I have recently been using a Vivitar 6-element enlarging lens that came with a Durst M305 I acquired, and I was just curious as to which manufacturer(s) Vivitar sourced their 6-element lenses from? It's 50mm f2.8, and is marked "lens made in Japan". I've heard that at one stage top Vivitar lenses were German, so this has thrown me a bit. Just curious, really, as it really does seem to be a good'un!

At one time Vivitar sold their VHE line of enlarging lenses after contracting with Schneider (as best as I can tell.) The VHE lenses had "Lens Made in Germany" marked around the lens barrel. The lens cells are identical in dimensions to Schneider's Componon line, and lens cells from a VHE barrel could be dropped right into an OEM Componon S barrel. I am uncertain as to who exactly in Japan made another line of Vivitar enlarging lenses, since Vivitar is known to shop around for different manufacturers for various lenses, both for cameras as well as for enlargers.

I had a Vivitar 150mm VHE lens it was definitely made by Schneider. Vivitar have always been a design house having their lenses made to their own specifications, their top of the range products have always been amongst the best, but as far as I know the only lenses Vivitar had from Germany were the VHE enlarger lenses.

Ian