Color noise at ISO 800

[PeterBrandt]

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Could you please help me, how to avoid color noise at ISO 800.

Have  a look at the two screen captures, first is the over all Thanksgiving dinner shot, second is a blowup of the lower part of the same photo.

 

Is there a newer program update to lower the noise. See the mottled yellow ! 

My V-Lux is a 114 type.

 

Is there a 3rd party program to smooth out the color noise?

 

Does the latest V-Lux over come this noise issue?

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[jaapv]

You don't need any other program to get rid of this problem. In fact, the best way to handle this is in the original raw conversion in ACR. Check your noise reduction settings in ACR, alter to get rid of the noise and save as default. It should never produce noise like this with proper raw conversion.
Another thing I notice that you are editing in 8 bits (and sRGB?) Do yourself a favour and set your raw conversion in ACR to 16 bits and Adobe RGB, only dumbing down to 8 bits and sRGB (if needed) just before saving.

You are not shooting JPG I hope? In that case get rid of the habit double quick - it is as bad as smoking, and far easier to stop.

[PeterBrandt]

18 minutes ago, jaapv said:

You don't need any other program to get rid of this problem. In fact, the best way to handle this is in the original raw conversion in ACR. Check your noise reduction settings in ACR, alter to get rid of the noise and save as default. It should never produce noise like this with proper raw conversion.
Another thing I notice that you are editing in 8 bits (and sRGB?) Do yourself a favour and set your raw conversion in ACR to 16 bits and Adobe RGB, only dumbing down to 8 bits and sRGB (if needed) just before saving.

You are not shooting JPG I hope? In that case get rid of the habit double quick - it is as bad as smoking, and far easier to stop.

Guilty ! jpgs.

If I shoot RAW, does my original DVD from the camera box give me a RAW conversion program ?

I guess then I'll see what ACR is !

Peter

[PeterBrandt]

maybe the extent of the blowup is part of the problem, see attached overall shot,

Peter

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[jaapv]

ACR is the raw conversion program of Photoshop, it will open automatically , but you may need to update.

I would advise you to read: https://www.amazon.com/World-Sharpening-Photoshop-Camera-Lightroom-ebook/dp/B002NQSMWW

You'll find a short synopsis here:

https://www.l-camera-forum.com/topic/216580-leica-m8-m82-m9-m9p-mm-mtyp240-faqs-questions-with-answers/?do=findComment&comment=2464083

 

 

[adan]

Peter - that yellow mottling happens when shooting under extremely yellow indoor lighting. And then correcting the white balance (either in post processing, or with the camera doing it automatically in jpegs.)

Essentially, the blue-filtered pixels of your sensor (and any color sensor) are virtually blind under strong-yellow light (e.g. light bulbs, as compared to the Sun's full spectrum).

Since you have Photoshop, you should be able to view the picture per color channel, and see just how damaged (splotchy and incomplete) the blue channel is, when a picture is taken under light containing virtually no blue light wavelengths. In PS menu > Windows > Channels.

Realistically, when there are few blue wavelengths, you may be exposing at an overall exposure of ISO 800 - but when white-balanced, the nearly-empty blue channel has to be so amplified that in that color (blue), you are shooting at an effective ISO 3200 or so (with equivalent noise in that channel).

Thus the yellow mottling = places where there is virtually no blue image to amplify. Zero times any amount of multiplication is still zero.

And, yes, the damage is so widespread that "noise reduction" techniques just can't smooth a wide-enough area to get rid of the mottling.

An example (from an M10, and raw, but same principle applies): note how "underexposed" the blue channel is, under yellow light.

Now - imagine having to recover midtones from that black blotch - which is what "white-balancing" will try to do.

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There is only so much software can do to avoid this - the only real solution is a bigger sensor, and thus bigger pixels. Or sticking to ISO 100 with the V-Lux's small sensor (1/8th the area of an M10 sensor), and being generous with exposure, and counting on the image-stabilization, so that the blue pixels get a reasonable exposure. Or use flash. Or switch to "daylight" 6000°K bulbs (which look a bit zombie-like to our warm-indoors-accomodated eyes - but are better matched to color photography).

This is the blue layer of your first screen shot - every piece of "black confetti" is a place where there is still no blue image (even with white-balancing), and thus they show as yellow mottling. Normal noise-reduction techniques can't get rid of those huge chunks - they work on "per pixel" noise.

[jaapv]

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Thanks, Andy. I learned something here.

[jaapv]

What happens, Andy, if we shift the black point in the blue channel (smart object - redevelop the blue channel in ACR)? ACR should give a shadow clipping warning as well.

[adan]

Not sure what processing you mean. Simply raising the brightness of black in the blue channel tends to produce "blue" blacks.

Generally, when I start seeing yellow mottling (and using RAW) I just go to the camera calibration page of ACR and reduce the blue-yellow saturation (which is not a bad idea anyway - Leica does like their "pure" yellows and blues ).

[Guest]

19 hours ago, adan said:

= places where there is virtually no blue image to amplify.

This holds for all yellow(ish) parts of any image!

Edited December 2, 2019 by Jossie

[jaapv]

3 hours ago, adan said:

Not sure what processing you mean. Simply raising the brightness of black in the blue channel tends to produce "blue" blacks.

Generally, when I start seeing yellow mottling (and using RAW) I just go to the camera calibration page of ACR and reduce the blue-yellow saturation (which is not a bad idea anyway - Leica does like their "pure" yellows and blues ).

Not the brightness, shifting the black point crushes the blacks.