Out of camera DPI
assuming you used the 12 million pixel setting, you will see that the physical size (NOT the file size in Mb) of the image at 72 DPI is about 6 feet by 4 feet. If you leave the "resample" box unchecked and change the DPI to 300, the size will reduce to about A3 and the file size in Mb will remain the same.
Hope this helps
|Fangorn Forest by cand1d|
|Yosemite Falls with Moonbow by Jonathan Shapiro|
from Best Landscape of the Week 4