Since the mount reports to the camera the default maximum and minimum values for aperture then I would expect that the errors would consist of these, any recorded EXIF data would show the wrong aperture though the exposure would be correct, except when the camera is set to it's minimum aperture in which case the exposure could be off by 1 stop +/- depending on what the default reported minimum aperture is.
J. C. O'Connell wrote: > I dont understand, what camaera funcitonss will not work at all or will > not > work properly compared to a real K-A lens > if there are no aperture contact pins like you state ? ? > jco > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > John Francis > Sent: Thursday, December 14, 2006 5:32 PM > To: Pentax-Discuss Mail List > Subject: Re: Question about Tamrons Adaptall2 mount for PKA > > > > Before I found an A* 300/f2.8 I used to own a Tamron, which I used with > the PK-A adapter (most of the time on my PZ-1p). It occasionally had a > problem similar to the one described below, where the "A" contact > between camera and lens didn't quite line up right, but on my PZ-1p that > contact was precarious at the best of times; I could break the contact > with my 80-200 mounted by simply pushing up slightly on the front of the > lens. > > I also found that the external mechanical linkage between the Tamron > lenses and the Tamron 1.4x TC had a tendency to disconnect. > > Apart from that, though, I found the combination quite usable. > > You don't get the full KA mount functionality, of course; there are no > aperture contact pins on the lens, so the camera doesn't really know > what the true maximum aperture of the lens is. But as the reading from > the adapter is f/2.8, which matched my lens, this wasn't a problem for > me. > > > On Thu, Dec 14, 2006 at 04:38:07PM -0500, Perry Pellechia wrote: > >> John, >> I have a Tamrom 90/2.8 marco lens mounted on a PKA adaptall mount. It >> > > >> works fine most of the time with both the *istD and the K10D. On rare >> > > >> occasions (only on the D, I have not seen this with the K10D) the >> contacts need to be reset (slight twist on the mount). This shows up >> on the camera body as if you mounted a "K" lens or as if you took an >> "A" lens off the A setting (Flashing F). A slight wiggle usually get >> the contacts working again. Overall it is a solid combination. >> >> On 12/14/06, J. C. O'Connell <[EMAIL PROTECTED]> wrote: >> >>> anyone have any long term experience using >>> Tamron's adaptall2 Manual Focus lenses with the PK-A adaptall2 >>> adapter? Do these work just as well a a true PK-A lens? Are they >>> reliable? Curious as I have a few adaptall2 lenses but havent ever >>> tried them with PK or PK-A mounts. Only >>> used them with M42 and Pentax ES/F mounts >>> with no functional problems but these mounts dont >>> have the electical communication the PK-A >>> mount has... >>> jco >>> >>> >>> -- >>> PDML Pentax-Discuss Mail List >>> [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net >>> >>> >> -- >> <----------------------------------------------------> >> Perry Pellechia >> >> Primary email: [EMAIL PROTECTED] >> Alternate email: [EMAIL PROTECTED] >> Home Page: http://homer.chem.sc.edu/perry >> <----------------------------------------------------> >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> > > -- Things should be made as simple as possible -- but no simpler. --Albert Einstein -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
