I took some photos at our companies holiday party last week and found that 50% of them were not focused properly. This led me to doing some research on the problem to see if it was my fault or the cameras. Since 50% were problematic I assumed it was my error and not the camera.
First things first. Download this document by Tim Jackson at focustestchart.com
Follow the procedure in the PDF file. Don't worry that it says D70 all over the place, this test works on any camera.
Now from doing this test and getting the results as indicated in the photo above, the focus problems I was having at the Holiday Party were not caused by ~6mm of front focus. So I am having another problem. I'm assuming it was due to the dim lighting in the room. Several times the internal flash had to strobe for focus assist. I'll need to keep an eye on this for future portrait sessions.
There used to be a way (and if you have firmware version 1.10 installed there still is) to go into debug mode and adjust the focus. However, if you have upgraded your firmware then it will not work as the key press sequence to get into debug mode has changed.
Here is the post to get into debug mode with the latest firmware.