Judging for all the complaints I've heard about AF inaccuracies with all brands of DSLRs, I think none of the AF systems are perfect. There is a range of acceptability built in to these systems. Whether it is acceptable to you is a personal decision.
A couple of points:
- First, I think this is noticable only in situations of very narrow DOF. Fast or long lenses.
- Second, when you shoot a focus chart, you are at very close range, and shooting under tungsten light. Tungsten apparently effects the AF sensors, and as DOF is a function of focus distance, DOF is even narrower.
- Third, if you haven't noticed it until now, in normal shooting, it probably is not a problem.
When all the stuff broke about th K10D front focusing, I test 5 of my lenses. 2 (35 f2.0, 50 f1.4) front focused on the test chart. I use both lenses on both the K10 and my DS routinely in everyday shooting, with no trace of the effect. When focus is critical, I manual focus. If you don't use spot metering, keep the Katz Eye, it is a huge help in critical focusing.
Hope this helps some
Cheers
-Alan