First, my question concerns an individual pixel/sensor from a CCD array of a digital camera.
From my understanding, the Digital Counts is linear with Exposure time. However, this line will be different for different light sources. My intuition led me to believe the Digital Counts of the different lines for exposure = 0 seconds would be the same.
Now, I could also take dark frames by covering the camera lens. I could take dark frames at different exposure times and estimate the Digital Counts for exposure = 0 seconds.
I also thought the value estimated for the Digital Counts at exposure = 0 seconds would be the same for both the light and dark data collections. This doesn't seem to be the case.
Can someone explain the Digital Counts at exposure = 0 seconds for the light frames vs the Digital Counts at exposure = 0 seconds for the dark frames?