|
Tim, the bias is there in every shot the camera takes, so this must be subtracted from every image we take, light, dark or flat, before we can do anything else useful with them.
Depending on the behaviour of your camera, the bias may be the primary source of noise for short exposures. For longer exposures, dark noise may become more significant. Once the bias is subtracted it may well look different as it should be leaving behind just the dark noise. Clear as mud?
|