As you can see in RAW data histograms, Green and Red are balanced perfectly (without any filters) in incadescent bulb light. You don't want to use any filters in this low-light condition, anyway.
Also, I don't think that 'gamut' is a good word in describing digital camera. Camera is sensitive to any visible light (to infrared - too), so camera gamut is equal (or broader) to human gamut.
We should describe camera behavior in terms of metamerism: some colors cannot be separated (i.e. same RGB(G) response for different colors)
As you can see in RAW data histograms, Green and Red are balanced perfectly (without any filters) in incadescent bulb light. You don't want to use any filters in this low-light condition, anyway.
Also, I don't think that 'gamut' is a good word in describing digital camera. Camera is sensitive to any visible light (to infrared - too), so camera gamut is equal (or broader) to human gamut.
We should describe camera behavior in terms of metamerism: some colors cannot be separated (i.e. same RGB(G) response for different colors)