Well... Fellow FA*600/4 owner Øyvind Hopland and I had a joint session trying to calibrate our lenses. None of us got consistent results. When focussing on the same subject, an eagle perched on a rock some 50 meters below us, we got widely different optimal calibrations. I don't recall the exact numbers, but we were on opposite sides of zero. Then we tried a closer subject, a lichen covered rock some 6-7 meters away. And got a different, also divergent, set of numbers. I gave up there and then, because the puffins were beginning to arrive. Øyvind has tried again later, but afaik he hasn't been able to make any sense of it yet.
I think there are other factors involved besides back- or front-focus. The MTF not very high, so telling the calibrations apart is more difficult than for, say, the DA*300/4. And camera shake is difficult to rule out completely. I would like to repeat the procedure with the camera and lens placed on a dampening surface, like a huge beanbag or something, to get a thoroughly vibration-free set of samples. As it stands, in the non-calibrated position, it has yielded a decent ratio of sufficiently sharp shots. Jostein 2008/8/15 John Whittingham <[EMAIL PROTECTED]>: > Hi Jostein > > Now I'm really curious/ > > John > ________________________________________ > From: [EMAIL PROTECTED] [EMAIL PROTECTED] On Behalf Of AlunFoto [EMAIL > PROTECTED] > Sent: 14 August 2008 21:06 > To: Pentax-Discuss Mail List > Subject: Re: K20D question for those that have one > > 2008/8/14 John Whittingham <[EMAIL PROTECTED]>: >> I really need to do the DA* 300/4 I would think adjustment would be >> more critical/beneficial with longer tele lenses, was there much >> adjustment required on the 600? > > I ended up turning it back to zero. > >> Was there a consireable improvement? > > No. > > Jostein > > > > -- > http://www.alunfoto.no/galleri/ > http://alunfoto.blogspot.com > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > -- http://www.alunfoto.no/galleri/ http://alunfoto.blogspot.com -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
