Even though the trucks were "coming towards me", I'd have to consider that, however slight, some panning was involved. It's been claimed by some that when panning they've found it a benefit to turn off the SR.
Jack --- On Sat, 7/18/09, AlunFoto <[email protected]> wrote: > From: AlunFoto <[email protected]> > Subject: Re: More K-7 AF observations > To: "Pentax-Discuss Mail List" <[email protected]> > Date: Saturday, July 18, 2009, 5:58 AM > 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. > -- 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.
