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Finally - the SD rolloff bug: FIXED!!!!!

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cinefeel said:
To BobNL:

You can avoid the yellow/red = orange problem if you select the band ranges carefully in Photoshop. You can also use Yellow -10 Red -+0 as an alternative, or as desired for your particular images.

I would also restate that my particular fix settings currently assume that your white balance is correct and you have left the SPP color wheel at zero.

Either way, you can simply use this fix selectively in the rolloff areas only, by using layers in Photoshop. This is probably the best idea until Sigma creates a deeper fix.

However, I would say that they cameras rendering of yellow at the moment is currently incorrect. I have seen this in my own photographs of yellow things.

Yep, the yellows are in some way looking unnatural or over- emphasized (besides the roll-off problem wich for me is a real problem...)

Also for example, Bob, the yellow jacket and skin tones in your recent Hip Hop dance duo shot looked unnaturally yellow to me. Interestingly, the embedded jpegs looked normal- suggesting that the mapping problem is in SPP and not in the camera.
Click to expand...
 
cinefeel said:
To BobNL:

You can avoid the yellow/red = orange problem if you select the band ranges carefully in Photoshop. You can also use Yellow -10 Red -+0 as an alternative, or as desired for your particular images.
Click to expand...
To be honest I saw that in photos that have a lot of colors in it (all of the rainbow) the result is a clear color cast. You are shifting colors so something has to break.
cinefeel said:
I would also restate that my particular fix settings currently assume that your white balance is correct and you have left the SPP color wheel at zero.
Click to expand...
Checked and checked. Although the question is what is the correct white balance?
cinefeel said:
Either way, you can simply use this fix selectively in the rolloff areas only, by using layers in Photoshop. This is probably the best idea until Sigma creates a deeper fix.
Click to expand...
Of course a possibility. That's what I did anyway if the problem was to obvious to me.
cinefeel said:
However, I would say that they cameras rendering of yellow at the moment is currently incorrect. I have seen this in my own photographs of yellow things.
Click to expand...
mmm, can't say that.
cinefeel said:
Also for example, Bob, the yellow jacket and skin tones in your recent Hip Hop dance duo shot looked unnaturally yellow to me. Interestingly, the embedded jpegs looked normal- suggesting that the mapping problem is in SPP and not in the camera.
Click to expand...
The yellow jackets actually were very much like irl. WB could be maybe a bit optimized but it was not far of. The girl in question has a greenish tone in her dark skin. We did multiple sessions with her and this always showed up with both Nikon and Sony alike. She always needs some extra work to get her pleasing looking ;)

Your approach to the roll off phenomena is a way to solve it for particular images but it is not a fix IMHO. I hope that people understand that. In order to find a fix we will need probably much more extensive research and changes. Not only on the level of hue change but luminance plays a big role too probably. I

--
Bob van Ooik
V-studio
----------------------------------------------
http://vstudio-magazine.de/
http://www.x3magazine.com/
http://www.flickr.com/photos/bobnl/
 
Going to post some new findings.

Depending on the color temperature of the light in your image, you need to shift the bands in my fix a little in order to get the right results.

HOWEVER, as far as I can tell, certain things remain constant:
  • You always adjust -15 Yellows and +5 Reds, give or take, in the same ratio.
  • You only need to adjust the bands, and BOTH RED AND YELLOW by the same amount of color degrees.
For example, if I shift the Yellow band +30 degrees to the right, I do the same with the Red band.

On a shoot you could perform this calibration with a color chart and then make a photoshop batch action from it if desired.

Will post samples.
 
BobNL said:
Your approach to the roll off phenomena is a way to solve it for particular images but it is not a fix IMHO. I hope that people understand that. In order to find a fix we will need probably much more extensive research and changes. Not only on the level of hue change but luminance plays a big role too probably. I
Click to expand...
Exactly. This is not a fix. Or at least - it is not likely to be a fix. The problem is too complex for simple manual hue changes in Photoshop.

To be able to fix it - you have to know better what you are doing.

--
Roland

X3F tools:
http://www.proxel.se/x3f.html
https://github.com/rolkar/x3f
 
Actually, this is simpler than I thought.

You don't even need to change the hue of the reds.

Just the yellow, and by closer to -10, as long as you make sure the yellow band is positioned correctly.

No other tones will shift, and there will be no color cast- not even in the yellows!

I am finding that there is a clear 'yellow noise' in the SD1 shadows that is quite aside from any color rendering issues.

Check this 200% crop out, click 'original' and view how only the yellow noise vanishes:





Same settings as other samples I posted in this thread, all NR off, etc. Ignore the CA from the crappy 30mm prime used.

I think the easiest way for Sigma to fix this problem might be to improve their NR algorithms to take this specific noise issue into account.
 
and thats why uniformed users must be aware that is impossible to have one "recipe" to fix all yor images.... the examles showed are mainly with one or two colors.....channg hue does affect all colors that have yellow and red...obviously....
Roland Karlsson said:
BobNL said:
Your approach to the roll off phenomena is a way to solve it for particular images but it is not a fix IMHO. I hope that people understand that. In order to find a fix we will need probably much more extensive research and changes. Not only on the level of hue change but luminance plays a big role too probably. I
Click to expand...
Exactly. This is not a fix. Or at least - it is not likely to be a fix. The problem is too complex for simple manual hue changes in Photoshop.

To be able to fix it - you have to know better what you are doing.

--
Roland

X3F tools:
http://www.proxel.se/x3f.html
https://github.com/rolkar/x3f
Click to expand...
--

To understand photography, you must understand that the experience must be much more important than the result ....
Carlos Roncatti Bomfim
http://weweh.com/
because men and women are different and we humans are the same.
 
...except that I just showed an image with both of those colors and nothing changed except the problem areas.

Look at the tape measure image.

I can add more, even landscapes. The fix is specific because the problem is specific. The only caveat is that you have to shift the color band of your hue adjustment depending on the color temperature of the image.

Because measuring white balance with Foveon is not a simple matter, you have to shift the color band manually until Sigma fixes their raw converter and/or noise reduction algorithms.

I'm starting to realise that this is a noise problem related to the classic Foveon 'red and yellow blotches', hence the red/yellow hue shift fixes. I have no doubt that a relatively simple Noise Reduction algorithm would be a pretty good fix.

Waiting to hear the latest from Sigma.
 
I agree with that.

The only end-all is for Sigma to fix their look-up-tables.

In the meantime, though, these kinds of fixes can salvage any image if you fine-tune them. Before, some images would end up unusable for professional work.

I would much rather Sigma fixes it- this is just an interrim solution.
 
Tried many Noise Reduction programs, found Topaz Denoise 5 is the best to treat SD1 noise so far - for skin tones and general pics. ACR NR makes skin tones worse.
cinefeel said:
...except that I just showed an image with both of those colors and nothing changed except the problem areas.

Look at the tape measure image.

I can add more, even landscapes. The fix is specific because the problem is specific. The only caveat is that you have to shift the color band of your hue adjustment depending on the color temperature of the image.

Because measuring white balance with Foveon is not a simple matter, you have to shift the color band manually until Sigma fixes their raw converter and/or noise reduction algorithms.

I'm starting to realise that this is a noise problem related to the classic Foveon 'red and yellow blotches', hence the red/yellow hue shift fixes. I have no doubt that a relatively simple Noise Reduction algorithm would be a pretty good fix.

Waiting to hear the latest from Sigma.
Click to expand...
 
when working with HUE - change the mode to Hue. when working in Saturation - change Mode to Saturation.
just my 2 cents.
cinefeel said:
...except that I just showed an image with both of those colors and nothing changed except the problem areas.

Look at the tape measure image.

I can add more, even landscapes. The fix is specific because the problem is specific. The only caveat is that you have to shift the color band of your hue adjustment depending on the color temperature of the image.

Because measuring white balance with Foveon is not a simple matter, you have to shift the color band manually until Sigma fixes their raw converter and/or noise reduction algorithms.

I'm starting to realise that this is a noise problem related to the classic Foveon 'red and yellow blotches', hence the red/yellow hue shift fixes. I have no doubt that a relatively simple Noise Reduction algorithm would be a pretty good fix.

Waiting to hear the latest from Sigma.
Click to expand...
--
Mike
 
cinefeel said:
Did you start with an image shot in Neutral color mode?
Click to expand...
Yes, I only shoot Neutral.
cinefeel said:
Also, did you try fine tuning the yellow band? This may be necessary in an image with tones close to the false color.
Click to expand...
I guess I could try that, but the results I saw were beyond a small tuning of the yellow band affected...

--
---> Kendall
http://www.flickr.com/photos/kigiphoto/
http://www.pbase.com/kgelner
http://www.pbase.com/sigmadslr/user_home
 
I don't think this is a colour balance problem, although you can reduce the effect by changing the colour balance.

I think it comes from calculations done with too few bits.
 
D Cox said:
I don't think this is a colour balance problem, although you can reduce the effect by changing the colour balance.

I think it comes from calculations done with too few bits.
Click to expand...
...., I can't help but think that the bit-level has a lot to do with this "problem"...., which has been with us since the SD9, imo....

...., 12-bit calculations just aren't enough.. (??)
 
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