Thanks for everyone who posted and all the advice...
As I said before, I was going to go out and do some accuracy testing on my camera to see if it was me, the lenses or the auto focus feature of my K-20D.
The Results are in...
There is definitely an issue with the Pentax DA zoom lenses that I have.
Let me first apologize for not including the lens data in my first post.
The lens I was using and that I use when I am out field shooting is an SMC Pentax DAL 1:4-5.6 50-200mm Zoom ED. (Purchased on Ebay...)
When trying to focus at full focal length, (200mm) it is okay, at close range, but not great.
After that, the lens will focus a few inches/ up to a foot beyond where the camera says it is in focus. At close focus the lens will focus within an inch of the subject so using a higher ISO and smaller aperture corrects that...
In my examples below you will see the comparison between the DA and my SMC Pentax 200M (The DA used an auto exposure of 1/500 @f8.0 the SMC 200M used a manual setting of 1/350 @ f8)
As you can see there is a world of difference...
Pentax DAL 200 Auto The focus here was supposed to be on the first red mark...
SMC 200 M 1/350 @f8
Thanks again for all the help!
Cheers
Bob