The back flange of K/M/A lenses are unpainted, and properly short out two of the many contacts on the 1.7x adapter. However, Pentax M42 lenses are painted in the same area, and by default don't short the contacts. I've have circumvented the paint on my M42 when used on the 1.7x by cutting a proper sized ring of foil, thereby keeping the lense alignment proper (which doesn't happen with just a small sliver of foil over the contacts. You don't have to worry about infinity focus, as the 1.7x adapter has enough focus control to get infinity even if the lens is set somewhat closer than infinity. You do need to prefocus somewhat so the 1.7x can achieve proper focus quickly. I tend to leave the lens on infinity focus for far objects and only focus closer manually when the subject gets closer. I've used this technique with a SMC Tak 85/1.8 with the 1.7x to get an 145mm f/3 lens that was exceptionally sharp with good bokeh considering the adapter use. Cheers, Gerry ----- Original Message ----- From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, April 26, 2001 7:06 AM Subject: M-42 I want to once again thank the group for the "spot metering" info! Another matter I'm trying to figure out is there any way possible to make a screw mount lens auto focus using the Pentax 1.7X Autofocus Adapter? Thanks......Craig - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
