So, if the temperature inside a DSLR is constantly increasing until it reaches some maximum based on the ambient temp...
How do any of the in-camera LENR darks match the temp of the lights, since they are not taken concurrently?
ICLENR darks taken before equilibrium in the camera don't match their lights cause they are not taken at the same time.
How is this different than darks on a cloudy night? Well, you say, they are probably closer. But they still don't match exactly and you are in the same boat as cloudy nights darks. You really have no idea what the temp of the light is compared to the temp of the ICLENR dark. All I think you can say is the ICLENR dark is going to be hotter than the light it is subtracted from.
You and I don't really know the sensor temp from the EXIF data. But whatever it is reading is what you have to work with. I don't think it is too wrong of an assumption to believe that whatever temp it is reading is going to be a consistent relationship to the actual sensor temp. So for all practical purposes, the EXIF temp is usable.
If you don't know the actual sensor temp, but you do know the EXIF temp, you can still figure that darks with the same EXIF temp as the lights are going to be the closest match you can get.
Then you get both the benefit of more signal from more lights, as well as the benefit of less calibration noise with a good master dark shot on a cloudy night in your garage.
LENR doesn't give you either of these benefits, plus the temp of the LENR dark is not going to exactly match the light anyway.
Personally, I believe that once you really believe that this stuff is critical, and you want to push the envelope to get the absolute best you can, then it's time to quit fooling around with a DSLR and get a regulated cooled astro-specific CMOS or CCD camera.
Otherwise, just shoot your darks on a cloudy night in your garage. And as the temp changes through the season, you end up with a library of darks about every 5 degrees or so. Since you are shooting them in your garage on a cloudy night, you can shoot hundreds of them to make a really good master dark.
Then you use bias frames and some program that does automatic dark frame matching, and it will scale your darks, and you will be doing about as good as you can with a DSLR.
Now, if I was shooting single frames, like Starscapes, I would be using LENR. That is a different case than deepsky.
Edited by Jerry Lodriguss, 02 October 2018 - 04:24 PM.