On 1/29/08, Doug Franklin <[EMAIL PROTECTED]> wrote: > Toralf Lund wrote: > > > I've never checked the actual motors, but I'm fairly sure there are > > "shaft encoder" components within the lens, which tells me that the > > setup is designed for a simple DC motor. They might still have swapped > > that for a stepper in later models, but somehow I don't think they have. > > I guess I'm just so used to cheap and small steppers produced in bulk > for other applications, at least since hard drives hit the main stream, > that I'd expected them to be cheap. Maybe it's tough to get enough > torque in a really small stepper. > > -- > Thanks, > DougF (KG4LMZ) >
That's a major issue, lens drives need more torque than an HDD, which is a very low-torque application for steppers. And of course there is slop in the screwdriver link that makes them less accurate. In-lens motors don't have the slop issue, so stepper-type drives are much more practical. -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
