You could try fixing it to the front of any lens that has the right diameter front and seeing how it looks. Wide angle adapters like that tended to introduce chromatic aberrations even on the lenses they were designed for though.
Thanks for the reply.
I just snapped that I needed to refer to the 1980 Victor Duncan catalog and now I see that it was designed for the Ang. 10 -150 film zoom lens, hence the 15x.
It converted the lens to a much wider 7.5 -112 zoom, and reduced the "minimum object distance" to one foot, which I believe is several feet closer than the unmodified lens.
It requires an "intermediate bayonet ring, " which I don't have. I imagine the three prongs on the rear of the retro-zoom would be twisted into the ring and the ring screwed to the front of the lens.
As the retro-zoom weights three pounds, I imagine substantial lens support would be needed.
For the curious, Victor Duncan asked $2,250 for the retro-zoom and they asked roughly twice that for a c-mount 10 - 150, with named lens mounts costing more.