The issue becomes the fact that film is FAR more forgiving of alignment errors than digital. Not to mention the fact that the AF sensor & Refle mirror needs to move with the imaging sensor and that essentially dictates the shutter has to move too. Add the fact that wider lenses require far smaller and more accurate movements of the sensor so it needs to be very precise. And it's a lot easier to toss around a lens in a helical than a mirror box, especially when the lens group's AF gearing is design specific.
The AX was just about a best-case implementation of body-based AF. The biggest issues with the concept were inherent, not implementation. -Adam 2010/11/12 Margus Männik <mar...@eol.ee>: > I know about Contax, I've even tested it years ago. AX autofocus wasn't > simply slow, it was a disaster. Still it doesn't mean that in-body AF > couldn't be done better - especially if we consider that instead of film > mechanism there's only a sensor to move. After all, weight comparison > between lens (group) and sensor chip is the cornerstone of in-body SR. How > many people said "it can not be done" before Pentax engineers just came and > did it? > > BR, Margus > > > > On 11/11/2010 11:58 PM, Adam Maas wrote: >> >> 2010/11/11 Margus Männik<mar...@eol.ee>: >>> >>> Want some crazy suggestion? ;) >>> Future Pentax bodies will have in-body autofocus. It's much faster to >>> move a >>> light sensor than tons of glass. And you'll have AF with any K-mount lens >>> (and others that you can mount via adapters) ever produced. Great, isn't >>> it? >>> Why it still has a focus-ring... hmm, well, it's for a backward >>> compatibility and manual focus, of course. >>> >>> BR, Margus >> >> In body AF has been done (Contax AX), it's MUCH faster to move the >> glass and far less trouble to keep aligned. >> >> -Adam >> > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
