Quote:
Originally Posted by RobF
Another question - perhaps same one worded differently. Why wouldn't R:G:B 4:4:4 hrs combined be just as good as say LRGB 6:2:2:2 hrs?
Is it to do with the difficulty of aligning the 3 colours to get a tight image with detail?
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As Bassnut said, it's because colour filters are only letting ~1/3 of the spectrum through, while Luminance is capturing the whole spectrum at once so many more photons being captured - much greater efficiency.
With RGB 4:4:4, you're only allowing 1/3 (probably less) photons through to the sensor the whole time you're imaging, whereas for LRGB 6:2:2:2 you've got six hours where the whole spectrum can come through. if you do the maths you're capturing about twice as many photons.