I recently got my D7100 back from Nikon repair (the auto-focus had stopped working). The auto focus is now working, better when I take shots indoors, but not-so-much outdoors. My main subject matter is birds. I've shot 3000 outdoor photos in the last two weeks, and maybe got 20 pics that were just ok. These few pics are still off and lack sharp details. All the others are so blurry I'm getting a headache looking at them. The indoor photos are better, but still not all perfect. I even tried some test photos of a focus calibration form, they seemed much better. I've also noticed a marked difference between photos taken in aperture priority and program modes. The program mode shots are slightly clearer.
I talked with Nikon and they asked me to send some photos in. And now I wait for an answer.....
In the mean time - I thought I'd look for some input from my friends here in the Nikon Forums.
Specs - D7100, 300mm f2/8, mounted on a tri-pod
Thanks for your expertise and input!!!