On 02/09/06, Toralf Lund <[EMAIL PROTECTED]> wrote: > Seems to me this all makes it similar in functionality to a traditional > step(per) motor. Technically it is even more closely related to a > piezoelectric motor, although I don't believe it's exactly the same thing. > > Both of which can come in packages that are identical to a traditional > DC motor, and could as far as I can tell be used in an in-body motor AF > system - which would cancel out the need for the traditional feedback loop.
A magnetic stepper motor could potentially be built in a ring format. Pentax has displayed a very practical solution in opting to use traditional fixed magnet linear motors in its SR implementation. Minolta on the other hand developed a new type of linear motor which whilst ingenious probably tied up significant of engineering resources as would have the development of the Canon USM system. Who knows, Pentax could pull another practical rabbit out of a hat and surprise us? Feedback loop would still be required though, much like the Canon system which apparently uses an optical strip. -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
