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Smoother portraits

One of the great things about the new Sigma (DP) Merrill cameras is the incredible amount of microcontrast they can deliver. The combination of the Foveon sensor and a perfectly matched lens make this happen. Unfortunately it has one drawback, portraits can look less flattering… But there is a simple way to fix this.

In Sigma Photo Pro you have control over the amount and the kind of noise reduction to be applied. Choosing here wisely will lead to much more pleasing portraits.

–In Sigma Photo Pro there are 5 positions for the “sliders” in the noise reduction tool. I named them simply 1 to 5 from left to right.–

The default settings

Chroma 3, Luminance 3

Chroma 3, Luminance 3 – the default

At this setting everything is visible like skin pores, small hairs, blemishes, molds and skin imperfections. This might work well for portraits of people with a lot of stories to tell through their face. But for the beautiful women I like to surround myself with this is not really acceptable.

From experimenting with the noise reduction sliders I’ve found that chroma noise reduction emphasizes especially blemishes and larger skin imperfections. By dialing it down the skin looks considerably cleaner.

The luminance noise reduction on the other hand has a big impact on the details. By increasing the amount of Luminance noise reduction the skin gets softer and things like skin pores become less prominent.

More settings

Below I show a few more combinations and what effect it has on a portrait. Be sure to click on them to see them bigger.

Chroma 5, Luminance 1

Chroma 5, Luminance1
Ultimate detail and microcontrast. Useful for portraits of street fighters probably but not so for beautiful women.

Chroma 3, Luminance 1

Chroma 3, Luminance 1
Dialing down the Chroma a bit gives it a slightly more pleasing look. But it still is too detailed for my taste.[/one_half_last]

Chroma 1, Luminance 1

Chroma 1, Luminance 1
Much more pleasing and incredible detail. Amount of detail is maybe a bit much though for women. But this could be a very useful setting for male portraits.

Chroma 1, Luminance 3

Chroma 1, Luminance 3
Now we are getting closer to a pleasing setting. Still a great amount of detail but the skin is already much smoother.
Chroma 1, Luminance 5

Chroma 1, Luminance 5
Very soft skin, might look a bit too much smeared though.
Chroma 3, Luminance 5

Chroma 3, Luminance 5
Looks quite similar to the previous, a lot detail gets smeared. Personally I like this less as you start to see more blemishes. Difference is subtle though.

Chroma 1, Luminance 4

Chroma 1, Luminance 4
My favorite setting. Detail and smoothness go hand-in-hand here. There is still plenty of detail but it is all much more pleasing.

Final note

Of course everyone has a different idea about how a portrait should look. But I hope this article gives you a bit of insight in the behavior of the noise reduction tool. I would advise you to experiment a little and find out what works best for you. Oh and it does not only apply to portraits of course. I’ve found for instance that my favorite portrait setting also does a great job at smoothing out some busy bokeh. Happy shooting!


The beautiful woman in the photo I used is my lovely girlfriend and soon to be mother of my child Olga Vasilkova. We met through our mutual love for the Foveon sensor and now almost 7 years later we are looking forward to receive the greatest gift on this Earth, sweetheart I love you!


  1. I just import the full resolution image after export from SPP5.5 into third party skin evening, smoothing programs. Plenty of them out there to chose from. Nice to see that you can do it all with SPP 5.5—but I’m still partial to the third party programs that I use. 🙂

  2. I’ve been using negative fill light instead as it also adds something of a soft glow reminiscent of the soft focus filters that were popular in film days, but I’ll have to try your setting as well now.

    Have you ever used negative fill for portraits, and if so, how do you think it compares to your NR settings?

    1. Mike, I think Negative Fill Light also has a positive effect but it also often means a loss of highlight detail. In such occasions it alters the processed photo too much in regard to appearance. That said I like to use -0.1 a lot as it gives me nicer contrasts.

  3. Thanks Bob: This demo and discussion really sheds light on the workings of Chroma and Luminance in a way I have never seen previously. I can see how it might also work on landscapes and cityscapes. I guess I will be testing this out on my photo going forward. A million thanks. Congrats on the soon to be new arrival.

    1. You’re welcome! It was quite a eye opener when I found out about this. Be aware though that there is a bug in SPP where the NR settings are not always correctly applied in the exported file 🙁

  4. I also like to use -0.1 negative fill light for softer looks. And I also wasn’t aware of the effects of chroma/lumi in terms of microcontrast … so thx for making me aware and good luck to you!

  5. Thank you very much for finding this out! I love this camera but the portraits had a bit to much information to say the least but now they look fantastic. Thanks again.

  6. Nice advice, somewhat reminiscent of the work that Carl used to do back in the day. Like others here I have tended to play around with the negative fill light but I will have to keep it in mind when I finally upgrade top the SD1 and/or DP3.

  7. Great article, Bob. And just in time! I am processing individual and couple shots from a gathering a few years back. We are all over 60 and so need something to look less real than nature has left us!! I’ll give this a shot right now.

  8. This is such a good quality article, but next week it will be three years old, and there have been no more feature articles since. What a pity! The world needs more of your good work!

    1. Thank you very much. I hope to pick up writing articles soon again. The last three years my time was mostly occupied by our now almost three year old daughter and a lot of professional photo work. Which meant my love for Foveon und thus this site were put on ice. With the little one now going to Kindergarten soon I hope I will have a bit more time to write 🙂

      1. Thank you Bob. Yes, I had a feeling that might be the cause, when I read in this very article that you were celebrating the impending arrival of your first born. 🙂 I hope you do indeed return to a situation with some time for this site, which is a mini-treasure.

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