Hi Cleon,
the DSLR cameras digitize with a resolution of 12 bits, and the newest to 14 bits. When you read the RAW file, you put each pixel value in 16 bit format *inside* PixInsight (ok, I know this is not the correct terminology). So each pixel value can be in the [0,65535] interval, but the camera raw image (in the particular case of your camera) has only values between [0,16383]. This means that you are employing only 25% of the dynamic range of the 16 pixel bit depth. So your saturated stars will be at 0.25 value (0=black; 1=white).
If you modify the RAW format preferences to have a brightness of 4, you are multiplying each pixel value by 4. So you will be expanding your pixel values to the [0,65535] range. This doesn't means that you have now better numerical precision. It simply means that you are multiplying your pixel values by a scale factor.
It doesn't matter if you do this multiplication. Only remember two things:
- Do it always with the same scale factor. Just remember that you were using 4.
- Don't use values above 4, because you will be clipping pixel values (those that exceed the 65535 value after multiplying by the factor.
Best regards,
Vicent.
