Wide angle backfocus

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

Re: Wide angle backfocus

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

Re: Wide angle backfocus

Brian, In the autofocus era, I doubt that many (if any) zooms are true ol'-fashun focus-preserving zooms--they all seem to be variable focal length lenses. That's certainly true of the lenses I can afford, anyway (including the fairly pricey 24-90, 16-45, and 10-17). Don't know about the

Re: Wide angle backfocus

Very few modern zooms are perfectly parfocal. It is best to focus at the focal length you are going to use. I haven't experienced any obvious focusing errors with the DA21 on either DS or K10D bodies; however, the focus is more accurate on the K10D. Finding the precise AF sensitive area is

Re: Wide angle backfocus

Just to clarify... Each of the zooms I tested correctly maintains focus as it is zoomed. If you zoom in, focus, then zoom out wide and take the photo, the photo is sharp as can be. If you autofocus while zoomed out, the autofocus moves the focusing collar and the photo is then back focused.

Re: Wide angle backfocus

On 31/01/07, 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. How does it