On Tue, May 19, 2009 at 09:06:05AM +0100, mike wilson scripsit: > ---- Graydon <[email protected]> wrote: > > On Mon, May 18, 2009 at 09:27:31AM +0100, mike wilson scripsit: > > > If I was Pentax, I would have a switch, worked by the screwdriver, > > > that turned the AF motor on/off, depending whether the driver was in > > > or out of its hole. Maybe a halfturn anyway, to make sure that there > > > was no slot to engage to. > > > > There are some edge cases -- like Tamron adaptall 2 adapters with a > > non-auto-focus lens attached to them -- that would make this a rather > > unfortunate default. > > Why?
Because the screwdriver is there on the adapter, but there's nothing in the lens to adjust. I don't want the camera body trying to turn something it can't to find out if anything adjusts. And yes I could set the camera body to MF before mounting the lens, but forgetting should not have dire mechanical consequences. > > The other part of it is that the camera really, really needs to know > > the focal length to auto-focus accurately. > > > > -- Graydon, who has tried to use focus confirm on the 500 while the > > camera still thought it was 800. > > Not by my understanding of how AF systems work. Is there something > different in the K10/20 systems? What they generally do need is a > decent amount of light. I think it's connected to the shake reduction. So far as I can tell in the case of the K20D, autofocus and shake reduction are really one combined system with different sensor inputs and mechanical parts, but which meet up in the electronic controls. -- Graydon -- 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.
