Good Question I don't own a Pentax DSLR (yet) but my understanding is that you don't have to use "green button" to meter with M42 lenses, you can get true continuous AE on the fly with M42 lenses on the D/Ds cameras. Reason for this is that because K mount bodies (none of them, film or digital ) don't activate the M42 aperture stop down "pin" then the camera knows that the incoming light is the real deal and wont change at moment of exposure. That way, no matter what you do with any M42 lens the camera can do true AE on the fly. Leave open or stop down the M42 lens or change the lighting , doesn't matter, still true AE. The whole reason for the "green button" kludge is that K/M lenses DO get aperture activation at moment of exposure and the camera doesn't know what actual it will be because the aperture sensing cam has be deleted. The green button thingy is for the camera to find out what the fstop will be and adjust shutter speed accordingly. The green button thingy for K/M is better than nothing but certainly not the same or as automated as true AE on the fly or true open aperture AE on the fly that nearly every pentax kmount SLR with AE has had for 30 years.
Someone please correct me if I am wrong about the M42 AE operation. Now I have a question, is there a stop down metered manual mode for M42 lenses or just on the fly true AE? In other words do you get both the true AE on the fly AND the green button one shot metered manual modes if you use M42? JCO -----Original Message----- From: jtainter [mailto:[EMAIL PROTECTED] Sent: Thursday, June 30, 2005 2:16 PM To: pentax-discuss@pdml.net Subject: M42 to D or DS Sorry to ask this. I know it has been discussed before, but I wasn't paying attention. How feasible is it to attach an M42 lens to the D or DS? Do you have to stop the lens down before metering with the green button? I know some of you have done it. Thanks, Joe
