Just to elaborate a bit, Zeiss makes AF glass for sony (ZA). They make their manual focus 35mm slr glass available in several mounts: Nikon(ZF), Pentax(ZK), M42 screwmount (ZS), and now Canon (ZE). All except the ZA series share the same optics. The ZA series is a completely different line developed for/with sony. They're manufactured in Japan, at "a lens production facility jointly chosen by Sony and Carl Zeiss." Zeiss designs and some Zeiss quality-control, but not Zeiss manufacture. To a large extent Sony outsources lens design to zeiss and buys the right to use the name, then has their lenses manufactured. The "real" zeiss glass is found in the other mounts.
Many of the new ZF, ZK, ZS, and ZE lenses are manufactured in Japan by Cosina to Zeiss specs (source: wikipedia
). I wouldn't be as concerned with the actual point of manufacture as I would be with the standards by which the lenses were made. From all indications, this seems like a continuation of Zeiss quality.
As far as manual focus goes, do any of you guys use a manual focus lens with an AF body? Using my [newly acquired hand-me-down] old Contax/Yashica mount Zeiss lenses adapted to my Canon 20D is quite a chore. I've been thinking of getting a split focus screen for the camera body because it feels so much more intuitive with manual focus.
Yeah, I don't particularly care where lenses are made, as long as they're good. It's just interesting background on the difference in heritage between "zeiss zeiss" and "sony zeiss".
On another note, I don't particularly care about a-mount glass at all anyway, since the system and it's overpriced glass doesn't really interest me.
The screens on AF cameras aren't particularly well-adapted for MF usage - they're more optimized for brightness. A lot also depends on the lens in question. The main difficulty in manual focusing my (af) 300 with, for example, a 2x tc on it, is that a tiny movement of the focus ring moves the plane of focus a very noticable amount. The viewfinder isn't really my primary limitation in this situation. Manual focusing my 10-20, on the other hand, is essentially impossible using just the matte screen. Viewfinder indicator lights that still work when manual focusing can help a lot in this situation. I don't yet own any MF glass, which obviously would deal with some of the handling issues (like on the 300).
I'm not sure how well split-prism focusing works vs. using focus indicator lights.