I spoke at length with HTC tech support. They are aware of the focus issue (once they contacted tier 2 support staff) and are working to correct it via software update. You can read the
acknowledgement that T-mobile posted.
Personal experience has been that bright lighting or very high contrast throws off the focusing. A picture of a check on a neutral table in a well lit room with no glare works well. A picture of a white check on a dark pine table with the overhead lighting causing the check to appear very bright doesn't work at all (at least, not for me). Outdoor shots on a cloudy day with a bright, white sky behind a darker subject cause severe focus problems for me. Indoor shots of spot-lighted artwork on the wall of a darkened museum don't work for me either.
While HTC was walking me through the standard troubleshooting steps, I noticed something very interesting in my test scene: a pair of dark shoes laying on a white sheet. The bed was illuminated by either direct sunlight through a sheer curtain or by a darker, very diffuse light from passing clouds shining through said curtain, depending on when I looked. When the diffuse lighting illuminated the bed, I could get a good picture. When direct sunlight illuminated the bed, the camera refused to focus properly, regardless of any attempts I made to set the focus point by tapping on the screen. During the entire time that the camera was pointed at the direct-sunlit bed, the lens was constantly refocusing; it made the image on the screen appear to be jumping constantly. I mentioned that to HTC as well.
It's a great phone, but I'll need to be able to use it outside or in high-contrast and brightly lit situations. Of course, your mileage may vary.