capture one_color noise reduction_problem

[studio347]

Hi,
I'm using capture one 6.3.3 with P65+, flash V2 profile, iso 50, sinar 4 by 5, schneider digitar 100 lens for still-life settings. I'm processing the files with Prophoto-16 bit, and working with the 16 bit tiff images in photoshop with ProPhoto setting.
When I shoot a saturated dark red object, for example red peppers, the preset color noise reduction, 34, seems to ruin the smooth color transition in the dark red area. The best color noise setting was zero, "0", where the transition is best. I guess that in this setting of zero, I'm not using any color noise reduction-function.
Is this a normal behavior of this software?
Do I need to adjust the color noise setting number each time depending on the colors and tones of an image?
I think I only had the problems in the dark red color areas. Are there any other concerns regarding the color noise reduction?
Let me hear some opinions...

Thanks in advance!

 

[Pics2]

I'm DSLR user, but I'm using P1 for years. I don't think you need any noise reduction at ISO 50.

 

[Jack]

It might help me understand your problem more clearly if you posted crops of the areas you're having issues with.

 

[studio347]

View attachment 59897

View attachment 59898

Here are the samples.
The first image was processed with automatic noise setting( 24, 35).
The second image was processed with color noise as zero, "0"(24, 0).

No sharpening was applied in Capture One 6.4.2 and Photpshop CS6. Just a simple curve at Photoshop.
It's a little difficult to see the problem here with jpegs(highest quality). But you can see more severe posterization on darker red color area of peppers in the first image.

In the second image, better tone transition in the dark area(better in my monitor with the tiff files), but there are some color noise( at the darkest shadow area of red) even at this ISO 50. Yes, I know that I'm being a little anal here since I'm checking the noise at 200% level of my monitor even though it shows at 100%.
Overall, zero color noise setting is much better. I can't trust the automatic setting(#35) of capture one when there are dark red colors from now on.
It was a little surprise to me.

Shot with P65+ with flash V2 profile, sinar 4 by 5, Broncolor strobe, schneider digitar 100, 1/250 S, about 7 feet camera distance from the subject, processed Prophoto 16 bit, 100 % file, converted Adobe RGB, perceptual, 8bit, jpeg(highest quality) in Photoshop, no image size change.