For Pentax autofocus to work the TC's have to have to transmit the FL. The TC's in fact simply pass data on the digital pin straight from the camera to the lens and vice versa. To do other wise would require the TC to make changes to the data stream, and frankly I don't think they're that smart, I doubt that any of them have any processing power at all, (except for the Pentax AF 1.7x adapter, which has about the same processing power as an F zoom lens, which is to say almost none). The ability to parse the Digital Data being passed from the lens to the camera find the correct bits carrying the aperture adjustment information and modify to account for the TC is well beyond what was necessary for the system to work, and would certainly add to the manufacturing cost.
John Whittingham wrote: > On Sun, 11 May 2008 11:07:53 -0600, William Robb wrote > >> This doesn't >> affect Pentax equipment (unless the AF converter transmits FL data, >> does anyone know if it does?). >> > > Both the Sigma EX teleconverters do transmit the lens FL, as do the Kenko > (Teleplus) SHQ 1.5x, 1.7x and 2x converters I have, yes I know I've got a > shed full of TC's. Please don't tell the lens police, they wouldn't > understand 8) > > John > > ---------------------------------------------------------------------------------------------------- > > The information transmitted is intended only for the person to whom it is > addressed and may contain > confidential and/or privileged material. If you have received an email in > error please notify Carmel College > on [EMAIL PROTECTED] then delete all copies of it from your systems. > > Although Carmel College scans incoming and outgoing emails and email > attachments for viruses we cannot > guarantee a communication to be free of all viruses nor accept any > responsibility for viruses. > > Although Carmel College monitors incoming and outgoing emails for > inappropriate content, the college cannot > be held responsible for the views or expressions of the author. > The views expressed may not necessarily be those of Carmel College and Carmel > College cannot be held > responsible for any loss or injury resulting from the contents of a message. > > ---------------------------------------------------------------------------------------------------- > > > -- Vote for Cthulhu. Why settle for a lesser evil... -- Dr. Jerry Pournelle -- 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.
