Had to use google translate.
I didn’t understood why feeding different iso value’s didn’t changed the preset in automode like other denoise things.
And a wile ago i read some comment about that prime is doing it’s thing before “iso-value in the raw exifdata” is used to “set” the brightness of you preview. Normal denoising is “attacking” noise caused by setting brightness value’s according to the ISO-value on the actual exposure value’s.
So with the actual “amplifying” is also amplified the noise on the imagedata which causes by removal smutch and smear. Thus los of detail.
( iso is kind of a ruler which defines the steps of measuring a signal and the smaller the measuringsteps, higher isovalue, the more the noise is measured with it as “signal” and became part of your image.)
By remove most of the (shot) noise reqocnised by the PRIME algorithm before adding the iso value on the exposuredata of the image you have less “noise” enlarged by isovalue to get the “taken image” in brightnes and thus less smutching and smearing in the jpeg.
So that’s why a preset of PRIME is no problem on multi iso images. The aggresion the PRIME is targetting the noise is done by setting the slider. I am not sure but i think it’s also using the HQ algoritm at the same time when you ramp up the slider to maximise denoising.
When i used normal after demosiacing denoising and nik define2 after that on a 6400iso i equaled this with 70% PRIME to let the jpeg looked the same.
40% is default and by preset 30% you leave some noise in the image which wil be not damage the lower iso value shots.
I used NIK define2 to get a feeling of agression in the slider of PRIME. Define2 is targeting left over noise in a tiff. So export a iso value type, well exposed, with as low PRIME % you think look good in the preview window, export a tiff to define2 and see if it’s sees more. Proces tif to jpeg and a direct prime to jpeg wile ramp up the slider. When they look the same you have reached the maximum level of usefullnes of PRIME. Go a tad back from this level and your fine. This can make some iso valued preset’s.
Me i don’t care some noise, so i only ramp up PRIME when it shows too much in the jpeg and i need to lose some detail to gain some cleaner look.
At least i think it works like this.(they don’t tell there kitchen secret. )