It's not conjecture that lenses without the pin are identified by Pentax DSLRs as A lenses ,and if the pin is blocked the camera shows the same behavior. The other connections are simply conductive on non conductive spots on the lens mount.on A lenses Even if digital pin simply powers the chip the effect is the same, without power the lens becomes "dumb". However there's no particular reason to make any of the previously existing pins part of the digital communication path and every reason to not do that if you care about backward compatibility as it might break the "A lens protocol".
James wrote: > On Mon, 05 May 2008 14:27:04 -0400, P. J. Alling wrote: > > In my mind, there is a lot of conjecture about the "digital" pin. > I believe that it is power for the lens chip. > Noone knows what is really going on with all the contacts except pentax. > Sigma have reversed enginered the contacts and maybe tamron got the info from > pentax. > > James > > > > >> Just a follow up on my earlier serious answer. The 1.7x AF Adapter >> lacks the digital data pin, (seen here >> at Boz's K >> mount technical page), on it's female mount. Without that pin there can >> be no communication between the lens and camera, so the camera has no >> ability to treat the lens as anything other than an "A" lens. >> > > > > > > > > -- Vote for Cthulhu. Why settle for a lesser evil... -- Dr. Jerry Pournelle -- 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.
