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RED-Problem EASY

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Hi All,

you might rfemember THIS thread on an issue which is well known to the SIGMA-community?!

Coincidently, I discovered a redicolously EASY way of overcoming any RED-Problems with such problematic RAW-files ... let's have a closer look:

Our RED-Problem ... we love it ... we hate it ....

View attachment 1700

As we know and as the histogramm clearly tells us. The RED-channel is obviously overdriven. Nobody really knows, why SIGMA's REd channel is that sensitive .... more sensitive than either green or blue-channels. The result is a large scale overdriven RED areas in the picture, that look like an ugly soup without any structures or details within. with the red channel fully driven, blue and green gain the upper hand and colours clip towards kindn of purple ... just watch it with my screenshot ... that is not, what garish red roses are supposed to look like!!

Solution is very very easy at hands! ;)

1) Just reduce colour Saturation within SPP to an extend that the red-channel comes under control ... watch the histogram! As you see ... colours are running flat now but structures become visible ... the roses become more and more plastic! Save your image this way!!

View attachment 1701

2) Just amplify colour saturation know with any suitable other picture-processing software! Now your roses regain their bright and lively colours ... your picture becomes brilliant and develops our beloved SIGMA 3D-look ... does it not?!

View attachment 1702

3) DONE!

View attachment 1703

Do not ask me why it works ....I do not know .... but it perfectly works! Just try yourself! ;)

See you with nice SIGMA REDs

Klaus
 

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Whoa! That IS simple. I'm trying this when I get home, because I've got some seriously burned-out flowers. :)
 
Great!

Hey!

Sigma should employ you to solve all their various colur issues!
Well done, Klaus.

Now we only miss a way to effectivly get rid of the green-magenta noise in underexposed parts of the picture.

kind regards
Øyvind
 
Hi All,
Nobody really knows, why SIGMA's REd channel is that sensitive .... more sensitive than either green or blue-channels.
I've noticed that this happends only in some situations and on some red nouances or wavelengths (like roses) so maybe because of the silicon's gradual light absorbtion - red is the last and, perhaps less sensitive - and Sigma tried to force more gain in red, resulting clipping in those wavelenghts.
What do you say?

On topic: Nice done Klaus! It really works!
 
I've noticed that this happends only in some situations and on some red nouances or wavelengths (like roses) so maybe because of the silicon's gradual light absorbtion - red is the last and, perhaps less sensitive - and Sigma tried to force more gain in red, resulting clipping in those wavelenghts.
What do you say?

On topic: Nice done Klaus! It really works!

I thought silicon was most sensitive to red, which is why IR is easy with digital cameras. I may be mistaken, but I'm curious if the IR-cut filter isn't actually strong enough....
 
I thought silicon was most sensitive to red, which is why IR is easy with digital cameras. I may be mistaken, but I'm curious if the IR-cut filter isn't actually strong enough....

Maybe, I'm not shure, but still, why this happends only on some wavelenghts?
 
Ok, I test this new easy method.


Here is the original.
View attachment 1707

Now, I desaturate just enough (not too much) to reveal washed out details and so the red in the histogram is no longer touching the right limit.
View attachment 1708

I save this file as JPEG. Then I open it again.......in SPP!

Resaturate. I noticed the histogram would not push the red back to the right limit, which is good.

The result.
View attachment 1709


All done in SPP. No other software. What do you think?
 

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I suggest that you avoid saving the intermediate de-saturated file as a JPG.

The ADCs in the SD14 are 12 bits, and you loose the details in the lower 4 bits when you save to JPG (8 bits per channel), plus the JPG format itself is lossy, compressing the image more at the expense of color details.
 
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