Paul, Thanks for the ideas. I shot at F/8 using single point autofocus to confirm focus at the center of the image. According to the depth of field calculator over at http://www.dofmaster.com, a circle of confusion of 0.007 mm (around the pixel pitch for the K10D, the total depth of field is around 16", so I think I've taken ultimate focus precision out of the equation here.
Note also that I did test with two prime lenses (50 F1.7 and 43 F1.9) and saw no right-to-left issues using the exact same test methodology.... --Mark Paul Stenquist wrote: > >Hi Mark, >I thought about this a bit. Are you testing with autofocus? Are you >letting the camera select the focus point? That would result in the >kind of inconsistency you report. In any case, the centering problem >has nothing to do with autofocus. It's an element alignment problem. >Test at f2.8 or f3.5 and use manual focus. Focus on a target on the >right side of frame. If your lens has a centering problem, the left >side of frame should be consistently out of focus. Multipoint >autofocus can't be depended on to produce consistent results, >particularly if your target is somewhat uniform. >Paul -- 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.
