Hey all,
out of academic interest and perhaps to help someone who is not sure about his/her master dark:
I built temperature matched darks at 5°C, 10°C, 15°C, 20°C, 25°C and 30°C. All taken with my Canon EOS600D at ISO 800, all 5 minutes subs, number of subs is 24, 22, 20, 50, 52, 62 respectively. Temperature readings are from the camera exif data and the singel subs are within +/- 3°C from the nominal value.
Screenshot "darks1" shows 1:1 zoom, all with the SAME screen stretch applied, parameters shown in the instance data. It is the auto-setting of the 20°C image. As one would expect, intensity is increasing with temperature.
"darks2" shows the same masters, each with it's INDIVIDUAL auto screen stretch. Not quite sure if the following conclusion is right, as I do not know what the auto-stretch does. It seems to me as if the higher temperature masters are not a simple upscale of the lower temperatures. The distribution seems different. My conclusion is, it is worth to match the darks temperature even if the optimize option in image calibration is used, as optimize is a simple linear approch that cannot change the distribution. Any thought about the topic is very wellcome.
Struggeling with the upload limit here is screenshot one....
