- Feb 11View Source
" image processing features are disabled... I have disabled all of them"
Not if you output JPEG. Turning off those settings only means that default transformations will be used to produce the image from the sensor data.
If you output RAW then most of these settings are irrelevant because no "image" is produced. the settings are encoded in the raw file exif data so that subsequent software may reference them but the settings are not actually applied to the raw data. The only exception may be if you set the camera for auto-dark subtraction (usually called something like "long exposure noise compensation"). Otherwise the RAW file is only data, not an image; e.g. raw data is not actually "color" but rather consists of filter matrix information (Bayer) that must be de-coded and interpolated to produce a color image.
" if a noise is constant, we can use noise reduction techniques to neutralise it, provided we can identify and isolate it."
That's not true for real noise. It is possible to filter out unwanted signals (which are sometimes erroneously called "noise") but noise = uncertainty (entropy) and cannot be removed. The sky is an unwanted signal that is easily "removed" via subtraction (set the background level when scaling the image). But the sky signal contains inherent uncertainty (Poisson noise) that remains in the image and cannot be removed (though it can be hidden via convolutions and such).
It sounds like you are more accomplished and knowledgeable that I originally thought (it can be difficult to assess these things via short posts). And you have the tools necessary to get results. Happy imaging!