@heckflosse Ingo, I’m not sure but it looks like Unsharp mask sharpening is not as strong when using Fast demosaicing as it is the using 3-pass algorithm. This may be the reason why @micha sees “artifacts” in sharpened images demaosaiced with the latter.
@sguyader Sebastién, If you look at my before/after comparison, which was with neutral profile (only difference was 3-pass vs. fast) you can see that fast leads to a softer image (though with more artifacts at the edges)
Hallo Sebastien, hallo Ingo,
as we can see in Ingos example, the 3-Pass might be clearer and sharper, but the artefactes are mor technical, geometric, unorganic and for me more ugly. Do you knows the reason? What is the best preset for Fuji raf?
(May I ask you, where you lives? I live in Germany and I am very glad, that you help me.)
Michael
Hello Michael,
I’m from Germany.
Afaik the intention of the 3-pass xtrans demosaic is to get better details, which for noisy images (high ISO) enhances the noise especially if you use sharpening on top.
For low-ISO images, the 3-pass xtrans demosaic almost always gives best results if you avoid too strong sharpening settings.
About the settings, I think @sguyader knows best, as he uses xtrans cameras
Ingo
Hallo Ingo,
hoffentlich darf ich Ihnen in Deutsch schreiben. Das fällt mir unendlich viel leichter.
Ihr Bild-Beispiel mit den Bücherrücken zeigt doch sehr schön das Problem, das mir bei RT auffällt:
Der gute Modus: 3-Pass erzeugt diese hässlichen Artefacte, diese waagrechten und senkrechten Pixel-Blöcke. Das sieht sehr unnatürlich aus. Im weicheren, weniger scharfen Modus: Schnell, sind nur halbwegs organisch aussehende, an Filmkorn und Rauschen erinnernde Pixelblöcke. Diese sehen viel organischer und verträglicher aus.
Wie kann man mit RT die Qualität von 3-Pass erreichen, ohne diese Aretefacte?
(Ich finde es super-klasse, dass Ihr mir da “einfach so”, helft. Ich danke Euch sehr.)
Michael
Die Artefakte können mit dem Median Filter in der Rauschreduzierung verringert werden.
Das geht etwas zu Lasten der Schärfe, ist aber immer noch schärfer als fast demosaic.
Left: 3-pass without median filter, right: 3-pass with median filter
Sometimes, activating False color suppression in the raw tab can suppress some unwanted artifacts.
@micha you said the jpg out of the camera is “excellent”, but I don’t agree. To me the in-camera noise reduction is too aggressive removes some details, and I prefer the look of the RT processed Raw, keeping some noise but also some texture in the fur (which is important in my opinion, for such a subject as the one you photographed).
Here’s what I came up with using RT. It has a bit more luminance noise than in the out-of-camera JPG, but it looks much more natural to me, and I don’t see annoying artifacts (look at the pp3 below if you want to see my settings):
ISO6400.RAF.pp3 (10.2 KB)
Hallo Sebastien,
I took your pp3 and the result ist realy good. Yes, the fur has more details with RT.
Is your setting, witch I can see in your pp3 the perfect for Fuji with high ISO? Or is it not possibel to have a optimum setting for a sensor?
What has to be different, when the ISO ist only 1600 and not 6400.
Would it be possible to speek Deutsch with you?
I thank you very much.
Michael
I’m sorry for the language, my high-school Deutsch is now limited to just a few words. But I think we under understand each other well enough in English.
I cannot say the settings I used ar the perfect settings for iso 6400. You have to try and see if it satisfies you.
Maybe you can lower noise reduction and micro-contrast with ISO 1600 images, but here again you have to try.
Sébastien
With your help, I see good progress in developping with RT. Again: thank you very much.
Without noisreductin, the image has so ugly “pixel-blocks” or artefaktes: 3, 4, 5 or 6 pixels together in horizontal or vertikal direction. This looks not organicaly. What is the reason? Is this a RT or a Fuji-X-trans probelm? I have seen, with Lightroom it is simmilar. Is this some kind of mistake or a normal phenomen of digital fotografie? Why are this smal “pixel-blocks” not seen when I use fast-demosaic in RT?
Does somebody know, whether Lightroom is fundamental better than RT? (I dont like to use Adobe, I am satisfied with gimp and co.) Can I have about the them results whit RT? That would make me very glad.
Michael
it all depends on the way you measure quality. without a clear definition, we can argue until the end of time. it is also very likely that the answer is highly subjective.
Unfortunatly i don’t understand german…
For what can i say, with xtrans rawtherapee is what i think the best converter (and not only with xtrans) 
.
Only advantage with lightroom with xtrans is better/much easier distorsion-vignetting-chromatic aberration correction (but as soon as rawtherapee will get lensfun integration, rawtherapee will win in this area too).
Lightroom and RT are just tools, and the best tool is the one you can wield skillfully.
2 Likes
Yes, but beware, it drastically reduces the colour resolution. And the more the image is noisy, the more it destroys colours.
So use it only when really needed!
I agree 100%. This is why I always shoot raw with my X20 (very small X-Trans sensor) and X100s. I was constantly disappointed with the noise reduction level, even set at minimum.
A little luminance noise is better than too much noise reduction. This allow to keep better local contrast and details that are usually flattened by NR algorithms
The quality, I am looking for is, how much the ugly artefactes are vilsible, as shonw in the jpg-examples bevore.
When I trye to eliminate this “pixel-blocks” I have to use NR, and NR makes the image unsharp and smeary.
This was my question: Is RT similar to LR, or is LR more capabel to produce a organiy looking picture?
Michael
I have no experience with xtrans nor lightroom. but the wise of internet frequently complain about the poor support for xtrans in Adobe products, mentioning RT as a good alternative. so I suppose there’s no fundamental advantage of lightroom here. although I 100% agree with @paperdigits: the best tool is the one you can master better…
@micha I also think you can lower the noise level by carefully setting your shooting conditions. ISO 6400 like in the example you provided is always to look very noisy. Also in this example phot, I had to dial in +1.6 EV, which makes the noise even more prominent. So, try to avoid shooting at such high ISO and underexposing.
I agree. I generally avoid using it, and I prefer having some artifacts (barely visible unless pixel peeping) than color smearing.
I find that quite a few demosaicing methods, e.g. AMaZE, have a crosshatching pattern. I have grown to accept it but it can be annoying when shooting conditions aren’t ideal and you end up with an extremely noisy image. Sampled from a random noisy raw (not RAF):
Red
Green
Blue
The crosshatching above is fairly mild, likely because of my unsteady hands; often the hatches are sharper and more distinct. This can be disturbing for Lightroom/ACR users but, when you stop pixel-peeping, FOSS solutions win in terms of resolution.
Hallo Sebastien,
I have now learned, (from you and the others in this blog), how to handle with noisy raf. In my examples I have chosen the high ISO, to have a bad “negativ”. Normaly I try to avoid this, but sometimes, I like to take fotos with littel ligth.
My most importent question is: What is the reason of this artefactes “pixel-blocks” (5 to 12 pixels in a ligne), you can se in my examples and also in the picture of the books from heckflosse. Is this a normal phenomen by digital cameras? Or is this a Fuji-problem. Or is this a RT-problem? Or, is this no problem, because in a normal foto-print, you do not se this?