The way I read that it would not be a problem in this case since I was focusing and shooting wide open. Any other ideas why the magnified viewfinder image would be so much better than the final result. Could my DA 16-45 simply "not get along" with the ist D sensor when it's wide open? So many have said what a sharp lens this is wide open, and my viewfinder agrees, it's quite puzzling.
Don > -----Original Message----- > From: Rob Studdert [mailto:[EMAIL PROTECTED] > Sent: Sunday, April 03, 2005 7:02 PM > To: [email protected] > Subject: Re: HELP! DA vs 28s-One More Time. (longish) > > > On 3 Apr 2005 at 14:57, Don Sanderson wrote: > > > Rob, in one of your posts you said: > > > > "Har told ya, also I suspect any visual focus error on > > the DA is likely due to a spherical field of focus." > > > > What exactly does that mean? > > Can a viewfinder and focus confirmation signal actually > > be wrong for one lens and OK for others? > > A D viewfinder is too small to be really critical, but > > with the 2x magnifier detail in the roof is very clear. > > Some lenses exhibit focus shift due to the effect of spherical > aberrations and > aperture settings. If you wish to negate this possibility then > you need to set > focus at the taking aperture. So yes VF confirmation wide open > can be wrong, > also most non-macro lenses don't guarantee a flat field of focus. > > > Rob Studdert > HURSTVILLE AUSTRALIA > Tel +61-2-9554-4110 > UTC(GMT) +10 Hours > [EMAIL PROTECTED] > http://members.ozemail.com.au/~distudio/publications/ > Pentax user since 1986, PDMLer since 1998 >
