D7100 always on?
On most modern computer controlled devices, ie phones, computers, camera, etc, OFF is not really OFF. The internal clock is still running and a lot more on your phone and computer.
Besides the shots left, it is also remembering your last settings and time.
|Global Reach by cjf2|
|Maligne Lake by Pete of Oz|
from - Mountain Lake - (Full Colours only + A Border)