Hi! I own an d7100 from the first date when was shipped on 14 march. I have some 10000 photos taked in all possible condition. I noticed the same predilection of focus jumping to background...even in most easiest condition for it in high contrast full daylight. In single point, single focus and with many focus confirmations in a row before taking the pictures. Even on the old d7000 I noticed something similar. With the both body I was in trouble to obtain focus consistency in controlled condition with reikan focal on his focus target. I have owned an d5100 an d7000 (that in the second day of purchasing was sended in service for calibration and returned with -25 compensation writed in firmware) and now an d7100 and on all the bodies the focus was inconsistent and hard to control... Another thing on d7100 with brand new tamron 70 300 usd ...when I put external flash on the hot shoe ...bang major back-focusing (when the light is dim enough) take off the flash bang everything is ok... And another ugly problem...banding...a lot of banding if u take -2,-3 underexposed jpg-s...like an blue storm sky just when the sun is going under horizon and try to capture the dramatic deep blue dark clouds.