Bruce, Very interesting. I'll have to give it a try. Regards, Bob S. On Sat, Aug 17, 2013 at 11:06 AM, Bruce Walker <bruce.wal...@gmail.com> wrote: > I think Matthew explained it pretty well. > > When you "focus and move" what you're actually doing is rotating your > neck, describing an arc, so that causes a slight change in distance > between the sensor and your new wish-to-be-in-focus point. This is > especially noticeable if you focus on a subject's nearest eye then > reframe. The arc you move through is significant if you are within a > few feet of the subject, eg with a headshot using a 50mm-e lens or > less, and especially with wide-open apertures. It's not so bad if you > are standing 12 feet away with a 200mm-e. > > When I'm shooting subjects at f8 with the 50-135 I can always > center-focus and reframe with no ill effects. I do not do that at f2.2 > with the DA*55 shooting close-in (head and shoulders). Guaranteed > fail. I move the focus point and carefully focus on subject's eye. > > > On Fri, Aug 16, 2013 at 10:19 AM, Aahz Maruch <a...@pobox.com> wrote: >> On Wed, Jul 24, 2013, Bruce Walker wrote: >>> On Wed, Jul 24, 2013 at 8:05 PM, David J Brooks <pentko...@gmail.com> wrote: >>>> On Wed, Jul 24, 2013 at 7:15 PM, Aahz Maruch <a...@pobox.com> wrote: >>>> >>>>> Let me rephrase: does anyone actually use manually-selected AF points for >>>>> handheld shooting? >>>> >>>> I use the single centre and recompose >>> >>> That doesn't work with large apertures and short teles or longer. It >>> becomes auto-defocus then. >> >> That doesn't make sense. Can you explain further? If you pick your >> focus point, half-press shutter (or lock focus/exposure), move the lens, >> shoot -- where does the defocus come from? I've certainly shot plenty >> that way. >> -- >> Hugs and backrubs -- I break Rule 6 http://rule6.info/ >> <*> <*> <*> >> Help a hearing-impaired person: http://rule6.info/hearing.html >> >> -- >> PDML Pentax-Discuss Mail List >> PDML@pdml.net >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly above and >> follow the directions. > > > > -- > -bmw > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions.
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