Its not...its saying that during the time you have had it on, the camera was using that much...but once the camer is off its no longer draining. It just reports who used the most during your time on. If you reboot your phone then it will go away until you use more programs.
For example, my gas tank gauge could say that going up a hill used 90% of my gas consumed during my trip and coasting used 10%. However, it wasnt eating up both during my trip.
david