I do not understand what you have posted. How can the camera set the aperture when Its turned by hand? If you just leave The fstop at minimum all the time you Are not really getting true program operation If the fstops are approximate, metering is stopped down, and you Don't get instant exposure when you fire The shutter LIKE PENTAX DOES. They may be Calling that programmed AE but its not The same as pentaxes programmed AE which is much better And without those degradations. We are talking About two different modes here with the same name Which is bad. Blame that on Chinon if they Call it the same as pentax's programmed mode. jco
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Adam Maas Sent: Sunday, October 22, 2006 5:19 PM To: Pentax-Discuss Mail List Subject: Re: Some observations on lens mount capability. Funny, but my Chinon CP-6 does programmed exposure (with two seperate selectable program lines) with K/M lenses. It does this by selecting the desired aperture, attempting to set it, then remetering to confirm. The Nikon FA does the same thing with AI and Ai converted lenses in Program and Shutter priority modes. AI lenses are functionaly identical to K/M lenses apart from their ability to mechnically communicate maximum aperture (the FA is one of two bodies which takes full advantage of that to allow matrix metering). So reality proves you wrong. -Adam J. C. O'Connell wrote: > K/M lenses cannot support programmed > Exposure modes because in programmed > Exposrue modes the camera choosed the > Fstop and the shutter speed based on > Light condtions. K/M lenses cannot > Have their fstops set by the body because > They lack the consistant linear stop > Down levers ( even non-linear compensation > Wont work because the lensse are inconsistant > If you try to stop them down by partially > Actuating the stop down lever). > > IF it were possible pentax wouldn't have > Bothered with A series lenses. > jco > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > Adam Maas > Sent: Sunday, October 22, 2006 4:23 PM > To: Pentax-Discuss Mail List > Subject: Some observations on lens mount capability. > > I've been thinking about exactly what K/M lenses are capable of, and a > few asides. > > First off, you can do at least Program mode with K/M lenses. In fact I > own a camera that offers this with K lenses(Chinon CP-6 Dual Program) > and another that does this with the functionally identical Nikon AI > lenses (Nikon FA). Shutter Priority is also possible if you are willing > to override shutter speed selection in some cases (the Nikon FA does > this with AI and earlier lenses) in both cases the camera double checks > the metering after stopping the lens down, the FA will override shutter > speed selection by up to a stop in either direction to compensate for > non-linear apertures, this only occurs at small apertures though. An > interesting capability of the CP-6 is you can limit the smallest > aperture the camera will select in program mode with the aperture ring, > the FA requires aperture to be set to minimum to work in P and S modes. > > So Pentax has never chosen to take full advantage of the automation that > > is technically possible with K/M lenses, even if they weren't designed > with this in mind. > > Nikon has never produced an AF body that fully couples with AI-S lenses, > > the F4 is the only one to fully couple with AI lenses. In fact Nikon > only ever made one camera that takes full advantage of the AI-S mount, > the FA. And Nikon is the only other maker with reasonable backwards > compatibility with its SLR mount, but it hasn't fully supported it's MF > mount since 1989 (when the FA was discontinued). > > -Adam > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
