Barry, thank you for the information.
By the way, I just came back from setting up for InterBEE and I passed by at panasonic and didn't look like they had anything for HVX200a.

We just shot two short films back-to-back, one on the HPX500 and the other on an HVX200 with a Letus Extreme. Yes you can get beautiful shallow DOF on a 2/3" camera, but nothing like what you can get with a proper 35mm adapter. 2/3" matches the DOF of 16mm film, but doesn't match what you can get from 35mm film.

And to add to Barrys response. It enables you to use a cheap prime lens.

Yes - being able to use an old set of nikons on my HPX500 would be simply lovely

Since I started off with Pentax M42 lenses (because I have few lying around), I'm searching more on net auctions.
I guess M42 mount lenses are not that popular (?), they are cheap!
So, far I have 85mm, 55mm (F1.4) and bidding 200mm and 29mm at this point. Does anybody have good recommendation to buy?
One draw back is M42 won't offer as much variations as Nikon lenses, I guess.

By the way, to make Brevis work with HPX and Fujinon lens, will the extension tube make it to be able to focus?

You'll probably only need the achromat and maybe one spacer ring.

I will try the spacer ring. Thanks.

It was the same on EX1, too, I guess the acromat is too thick instead of needing a spacer.

Or does the spacer go to the 35mm lens side?

I put the extra achromat ring and another filter thick spacer and now HPX works fine. The whole length is crazy though, wonder how it is going to be with the flip unit, it makes it even longer!