Hi Flavio, I've also been through this and I ruled out routine tampering with lens mount. But if you limit trap focus to close up work only (not just macro but say a 300mm pointed to a bird nest 2 m away) , then it's more convenient to use a small, 12 mm KA macro tube. It's a cheap and safe piece of equipment, and you only loose infinity where, to quote our Caveman, there's nothing interesting anyway. ;o) Servus, Alin Flavio wrote: FM> Hi all, FM> after my recent acquisition of a Pentax 100/2.8 FA macro lens I've been FM> asking around for a way to make trap focus work with it. FM> There have been some speculations and suggestions by David Mann, Gerald FM> Wang and Jo McAllister but nothing too specific. FM> A little experimentation based on the discussion during the weekend gave FM> me the answer: FM> On the KAF mount there are seven contacts and the AF shaft. Looking at FM> the camera mount you have from left to right two contacts for the FM> aperture info, the "A" contact then 3 more aperture info contacts. FM> These are also present in the KA mount. FM> The KAF mount has a seventh contact (gold plated on my Z1-p). Insulating FM> this contact will have the lens behave as a KA manual one. FM> I used some Scotch tape for this but I'm not sure if frequent use of FM> this could leave some adhesive on the contact and produce malfunctions. FM> You also have to tape down the AF shaft, in order to disengage the AF FM> motor, otherwise manual focusing will generate some spurious current in FM> the motor possibly damaging it. FM> So with a couple of small piece of tape you get an AF lens trap focusing FM> as a MF one. I didn't experiment too much since I had film in the camera FM> and I didn't want to waste too much but it seemed to work fine. I'll FM> check again as soon as I have time. If there's anyone interested please FM> let me know the result of any further experiment. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Visit the PUG at http://pug.komkon.org.
