I can't imagine getting the non-CAC version of these lenses; definitely by all means get the CAC.

I did an article on CAC over at DVXUser, and I showed the same lens shooting the same shot, with and without CAC enabled. It makes a huge, massive difference.

*accordingly, I'd never want to put one of these CAC lenses on a non-CAC body! If you did, you'd get massive purple & green fringing.

A regular expensive properly-coated lens on a non-CAC body, that's okay.
A regular expensive properly-coated lens on a CAC body, that's also okay.
A cheap CAC lens on a CAC body, that's also okay.
A cheap CAC lens on a non-CAC body, that's ugly.
A cheap non-CAC lens on a CAC or non-CAC body, that's also ugly.

Barry,

ah, I guess you won't be able to turn off the CAC on the lens side, I thought CAC is done electronically.

Dean,

Yeah, drop by.

The lens itself doesn't actually "do" anything, other than report its focus position and zoom position to the body.

The body does all the work; the computer inside the camera does the chromatic aberration compensation.

But the reason you wouldn't want to put a CAC lens on a non-CAC body is: the non-CAC body won't be able to compensate for the aberrations. And a CAC lens is therefore going to be sending a whole lot of purple and green aberrations through!

CAC lenses are cheap because they don't bother doing all the optical coatings to correct out the aberrations. So a CAC lens on a non-CAC body means that no aberration correction is being done anywhere. That means fringing could run rampant through your picture.

Ouch, Barry... I'm sure you're right, but I would hope that some correction would be done and that the powers that be wouldn't depend totally on electronic compensation. I mean, after all, in the world of HD $6,500 may be cheap, but in the "real" world that's a lot of money. You can get a pretty good used car with a full tank of gas for that.

I have the Fuji w/o the 2x and I have been really trying to be critical (I've shot 16 and super16 for 30 years, so I've learned to accept some compromise) but the image looks pretty damned good to me, so if what you say is true, CAC is akin to the proverbial sliced bread...

Yes, but you can't buy a high-def lens with optical correction for that! People have been spending at least 5x to 10x that much for proper HD optics.

I'm sure that true optical correction would be better, but for the price, yes, CAC is indeed the sliced bread revolution.