Cory, At the bottom of that web page is the following:
"NOTE: This modification will not permit shutter-preferred or programmed autoexposure and will not allow K and M lenses to be used on the new *ist and *ist-D cameras (or the ZX-30/MZ-30, ZX-50/MX-50 or ZX-60/MZ-60)." Since that web page was created Pentax released a firmware upgrade to allow the *istD to do stopdown metering with the green button, and the *istDs was released with that ability (via a different button). But when the istD was released it could only meter with pre-A lenses at wide open aperture. You're correct in thinking that it's a gear limitation preventing the conversion from working, but it's not in the firmware - it's in the hardware. The cameras named don't have a mechanical relay for the aperture setting, they depend upon electrical data relay only. The mechanical relay is a legacy of the original K-mount of c.1975. The A lenses introduced the electrical contacts between camera and lens, but for the sake of compatibility the two systems co-existed in cameras and lenses for some years until Pentax finally began to drop mechanical linkage on cheaper models. But when the *istD appeared without mechanical linkage there was a great wailing and gnashing of teeth, because this was not a budget camera to be dismissed as a newbies' camera. Pentax had sent a message that it would not maintain full backwards and forwards compatibility forever. regards, Anthony Farr > -----Original Message----- > From: Cory Papenfuss [mailto:[EMAIL PROTECTED] > > Hey all... I've been playing with some older lenses I've got with > my *ist-DS, and I figured I'd try my hand at modifying a lens to have the > electrical contacts. Basically, the same modification as outlined here: > > http://www.robertstech.com/matrix.htm > > After successful completion of drilling jigged divots, I still > cannot get anything other than center-weighed metering. Upon further > examination, it appears that even on an official KA lens with insulators, > if the aperture ring is set to other than 'A', center-weighed metering is > used. Looking through the manual, it says that multi-segment metering > requires a 'A' lens or greater, but doesn't actually say it must be *set* > to 'A'. Is this a limitation in the firmware on this model? Apparently > on some bodies (like Mark's) it should be possible once the contacts are > set to inform the camera what aperture ranges it can do. > > -Cory >
