Sky was clear all night last night so I took two data sets of Lagoon and Trifid with the in camera noise reduction on and off.
Noise reduction OFF
Canon 5DH, ISO 1000, Hutech LPR filter, 100ED with Astrophysics focal reducer so 640mm at F6.4. 15X7minutes. Raw converted to 16bit uncompressed fit monochrome. darks,bias and flats same. Stacked as Tiffs in RegiStar digitally developed with ImagesPlus Richardson-Lucy enhancement and stretched
Gone
Noise reduction ON
Same as above except only used flat calibration in 16b uncompressed, all done with 16bit Tiff Flat was also colour balanced to grey, hence the colour difference
13X7minutes
3MB
http://members.optusnet.com.au/~avan...GTR_CFA_ON.jpg
No independant adjusting of colours or curves etc. Only digitally developed using same parameters. Richardson-Lucy enhancement to both at same settings and then stretched.
The size does not reflect any difference in quality. Both originals over 12MB.
I will let you be the judge which is better.
Bert