I see a lot of backfocus shots on my D. I did some tests with long manual glass (500 mm) and couldn't reproduce backfocus. The focus light in the viewfinder aligned with my manual focus and pixelpeeping confirmed this. I think I need to do some tests with the 16-45 on 16 mm. Also called Pentax benelux last year and they never heard of backfocus problems.... Since the focus is correct with long glass I wouldn't dare tweaking with the focus adjustment.
Toine On 1/30/07, Brian Dunn <[EMAIL PROTECTED]> wrote: > > I received a 21 Limited. Center only autofocus always greatly back focuses on > both ist-DS cameras, more on one than on the other. The 45 degree focus > chart showed the 21 Limited back focusing almost off the far end of the > paper. > > I tested other lenses and found that they all back focus when set to wide > angles. The amount seems to be proportional to the angle. For example, you > could set a 16-45 on a tripod, aim at something 7 feet away, zoom in to 45mm, > focus, then zoom out and focus again. The more you zoom out, the more the > autofocus changes. > > All this time I have been zooming in, focusing, zooming out, then taking the > picture. It works fine until you get a wide prime like the 21 where there is > nothing to zoom. When aimed at something across the street it tries to focus > past infinity and hits the stops. > > Research on the Internet finds discussion about adjusting three screws under > the base plate of the DS. These hold the auto focus sensors and you can > adjust for front or back focus. > > So I'm wondering if anyone here would care to take a 16-45 or 18-55 or the > like, zoom in and aim at something across the room, see on the focus scale > what distance it chose, then zoom wide and focus again to see if it changed. > Do all Pentax digital cameras back focus at wide angle? > > Has anyone here tried the adjustments under the base plate? > > Has anyone had a Pentax repair center successfully fix this issue? > > > Brian > > -- > > Brian Dunn Photographic > http://www.bdphotographic.com > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
