Originally posted by ProfessorBuzz Battery drain of course due to holding the mirror up and shutter open
Not actually for these two, but for holding the lens aperture open.
I will be reporting on power drain during exposure in the next couple of days. For A lenses and newer, the power use during an exposure is the same as when the camera is in idle, if the aperture is wide open. It is only when the lens gets stopped down that the power use is higher. Of course, activating mirror up/down and shutter open/close does draw quite a power surge, with current draw of 2 or 3 amps! (but only for a few milliseconds)