Could be, of course. For the DA*300/4 anyway. However the %-wise improvement is comparable for the two lenses.
Jostein 2009/7/18 Jack Davis <[email protected]>: > > The test having been done hand held, might one factor have been the K-7's > claim of improved SR.(?) > > Jack > > --- On Sat, 7/18/09, paul stenquist <[email protected]> wrote: > >> From: paul stenquist <[email protected]> >> Subject: Re: More K-7 AF observations >> To: "Pentax-Discuss Mail List" <[email protected]> >> Date: Saturday, July 18, 2009, 5:20 AM >> Good to know. It's what I suspected >> based on use, but it's nice to >> know that my suspicions aren't just wishful thinking. >> Thanks for >> taking the time to test. >> Paul >> On Jul 18, 2009, at 7:09 AM, AlunFoto wrote: >> >> > Better quantified this time. >> > >> > Yesterday I took stance on a bridge above a highway, >> and photographed >> > large trucks coming towards me. The speed limit at >> this place is 100 >> > km/h, and on top of a gentle slope. I shot series of >> each truck, and >> > have tallied the percentage of out-of-focus shots from >> each series. >> > The cameras were set to: >> > >> > - SR on for shots with DA*300, shot freehand >> > - SR off for shots with FA*600, shot from tripod >> > - AF-C, multipoint >> > - ISO 800 >> > - Av-mode (aperture set to f/8) >> > - DNG file format. >> > >> > Focus was judged by 100% view in Adobe Bridge CS4 >> without rawfile >> > conversion. I took a conservative attitude, judging >> anything that >> > wasn't perfectly sharp on the car front as >> mis-focused. I typically >> > looked at details in the grille (hope it's the right >> word?) or the >> > number plate. >> > >> > Between each series I allowed the camera to save all >> files before >> > commencing a new series, to make sure camera speed was >> not held back >> > by a full buffer. >> > >> > K20D + DA*300/4: 13% mis-focused, averaged over 9 >> series >> > K-7 + DA*300/4: 7% mis-focused, averaged over 7 >> series >> > >> > K20D + FA*600/4: 43% mis-focused, averaged over 7 >> series >> > K-7 + FA*600/4: 25% mis-focused, averaged over 11 >> series >> > >> > Each series held between 10 and 19 shots. >> > >> > Both lenses are focus-calibrated with the K20D, but >> not with the K-7. >> > I therefore suspect that the K-7 results could be >> somewhat improved. >> > >> > There are bound to be many unchecked sources of random >> variation here. >> > One is whether the trucks had cargo or not. If empty, >> they bounce a >> > lot more and could introduce motion blur. I suspect >> the 600mm shots to >> > be affected by this. With the small number of series, >> I can't rule out >> > that the two cameras have got an uneven share of empty >> trucks. However >> > I did the same experiment, at the same place, five >> days ago with the >> > K20D only, and the results from yesterday seems >> consistent with my >> > previous results. >> > >> > So all in all, the real-life numbers pretty much >> mirrors the nominal >> > doubling of the frame rate. Not the subjective feeling >> that the K-7 is >> > _more_ than twice as fast. Not in this situation >> anyway. However this >> > test, tracking approaching objects, is very different >> from panning a >> > bird flying from one side to the other. >> > >> > 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. >> > > > > > -- > 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.
