On 06/12/06, Bob Sullivan <[EMAIL PROTECTED]> wrote: > It's those little bumps on the lens mount that make the electrical > contact for reading info from the lens. Turn the aperture from f22 to > 'A' and watch the last bump in the series move up 1 mm - contact! If > you don't have 'A' set, you don't need the chip's mtf info.
The "A" contact retracts to sever contact in early lenses to indicate that the lens is not in the "A" position however on later lenses it is continuously spring loaded. Aperture range information is decoded by the contacts on the body however later lenses provide ID info and MTF data which are stored on a ROM inside the lens. -- 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
