#2. "RE: Is this the D5100 'backfocus' problem?" In response to In response to 0
I agree - backfocus to any significant degree is much more of an urban myth than reality. Certainly there is no systemic issue related to the D5100 or releated cameras.
The issue is typically user error based on one of the following: 1) photographer motion 2) slow shutter speed 3) subject movement 4) wrong aperture (too shallow) 5) AF sensor missing target 6) AF sensor on target but focus not achieved 7) Aperture or focal length that normally is soft (any of the extremes)