The first thing you should do in data calibration is to try to create a very good Bad Pixel Map of your sensor.
A good Bad Pixel Map will correct all bad pixels of your sensor.
Bad pixels are pixels that don’t behave linear.
We have two types of bad pixels, cold and hot:
- Cold Pixels – these pixels are either defect are respond really bad to incoming photons (and/or the dark current of your sensor). These will be detected using flat frames.
- Hot Pixels – these pixels respond very strongly on incoming photons (and/or to the dark current of your sensor). These will be detected using dark frames.
For the detection of the cold pixels, only a couple of flats are needed to extract them robustly and add them to the bad pixel map.
For the detection of the hot pixels, you need to supply at least 20 darks and more is always better in this case.
The Bad Pixel Map is a Master Calibration frame that you only need to create once per year or a couple of years. ( I have been using one successfully for more than 3 years now for a Nikon D5100 BCF mod, firmware hacked with the nikonhacker true dark current patch).
Thank you Sara for making this tutorial 😉 !
Posted on Sara’s website as well: