#4. "RE: D5100 + Nikon AF-S 35/1.8G autofocus problems" In response to In response to 3
Welcome to Nikonians! Sorry to hear of your problem. The issue could be the lens and not the body. Go to your local Nikon Dealer and try another copy of the 35mm f/1.8G AF-S on your camera. If the problem continues with another lens, the issue is likely in the body. If another copy of the lens works correctly exchange it for a new one (assuming you are still within the exchange period) or send the lens to Nikon Service for adjustment. Good Luck and Enjoy your Nikons!