What you really want to do is get the 1/2 to 2/3" adapter and get a really nice 19x lens for about a grand or a 22x for a bit more. There are also a lot of really nice 1/2" lenses out there too. We have two DSR-300 Sony cameras with 18x lenses. We can shoot a solid torso shot at 85 feet. I have a Century 1/2" doubler that I would sell, also.
It's a dry heat!
Sony HDCAM F-900 & HDW-2000/1 deck
5 Final Cut (not quite PRO) systems
Sony HVR-M25 HDV deck
2-Sony EX-1 HD .
Regarding the 1/2 inch Century doubler:
Does that go between the camera body and lens? If so, it seems to contradict what the Century sales person told me. He said that Sony has a non standard fitting to the fujinon lens, and that did not have a 1/2 that would work. Have you tried yours on an ex3