Need Help: Canon DPP Noice Reduction terms

Started Mar 14, 2009 | Discussions
tmyuen Regular Member • Posts: 183
Need Help: Canon DPP Noice Reduction terms

I'm learning RAW processing/retouching using Canon's DPP software. Can someone please help explain the terms "Luminance Noice" and "Chrominance Noice"?

Understand what circumstances should I apply Luminace Noice reduction, Chrominance Noice reduction, or both?

AdriaanMeijer
AdriaanMeijer Veteran Member • Posts: 3,047
Color noise vs luminance noise
1

Luminance noise is noise where only the brightness of a colored pixels is affected (but the color as such is (quite) allright).

Chrominance Noise is noise what shows up as clearly colored pixels (like a pixel green and another pixel red).

More often than not both kinds of noise will be in a single photograph.

So what to do?

Zoom in very much (I would start with 200%) and play with the sliders, starting with NO noise reduction. Perhaps you can see the two types of noise and the effect of both sliders.

But before being satisfied with all noise removed, do step back to a broader view (zoom out) because these noise reductions do tend to make the photos less sharp. Somewhere in between is an optimum, but where it lies is a question of taste too.

Besides, other photoprocessing software has these two noise reduction options as well, perhaps under slightly different names.

tmyuen wrote:

I'm learning RAW processing/retouching using Canon's DPP software.
Can someone please help explain the terms "Luminance Noice" and
"Chrominance Noice"?

Understand what circumstances should I apply Luminace Noice
reduction, Chrominance Noice reduction, or both?

I quickly searched a photo with both types of noise. This is NOT a perfect example of a good photo (it's a OutOfFocus part of an underexposed background), but it shows them in Lightroom (see the sliders on the right).
These are 4 screencuts, each at 200%.

Click on the picture to see the comments on the right.

Hope to have been of service.
--
All in my humble opionion of course!

(I might get a preposition wrong -or any other word for that matter-. English is a nice language, but it's not mine)

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OP tmyuen Regular Member • Posts: 183
Re: Color noise vs luminance noise

AdriaanMeijer,

Thanks for the response. Now I have better understanding of the terms.

If I may, I would like to ask a few more questions: What causes those noises (Luminance and Color) to be introduced in the image? the lens, the CCD/CMOS sensor, or high ISO setting? Is there any way to avoid those noises when taking photos?

BTW, these noise things come to my attention when I recently shot a few photos with the Highlight Tone Priority feature enabled on my Canon 450D. The IQ is obviously affected by those noises so one lesson I learned is to disable the feature unless absolutely needed. But are there other pitfalls that I should avoid?

AdriaanMeijer
AdriaanMeijer Veteran Member • Posts: 3,047
Re: Color noise vs luminance noise

YW

Noise is introduced in the electronic part of the camera. That is (mainly) the sensor and often the arithmatic involved.

Things that influence the amount of noise are (to my knowledge)

  • sensorsize (as well as the size of individual pixels). So a larger sensor has less noise.

  • ISO. Higher ISO gives more noise

  • exposure. Little light (Extremely with underexposure) gives more noise. As does longer exposure times (like in shots of startrails). part of this is caused by heat of the sensor.

Apart from the sensorsize I always think of it as if with little light the sensor sometimes 'makes up' (or estimates) values in stead of mesuring them. So the dark areas of a photo are more affected, the underexposed parts are more affected and a high ISO is more affected (whether it's true or not, it's an easy to remember rule of thumb and it does make sense).

I don't know whether the one kind of noise has to do with other things than the other.
--
All in my humble opionion of course!

(I might get a preposition wrong -or any other word for that matter-. English is a nice language, but it's not mine)

 AdriaanMeijer's gear list:AdriaanMeijer's gear list
Canon EOS 7D Canon EOS 600D Canon EF-S 17-55mm f/2.8 IS USM Canon EF 70-200mm F4L IS USM Canon EF-S 18-55mm f/3.5-5.6 IS II +5 more
OP tmyuen Regular Member • Posts: 183
Re: Color noise vs luminance noise

Can't thank you enough for alll the help

JustinRebbert Regular Member • Posts: 465
Re: Need Help: Canon DPP Noice Reduction terms

Here is a quote from the review here at DPR for the Nikon D80:

"Onto noise, Nikon's approach, as it always has been, is to use more chroma noise reduction and leave as much luminance (detail) information intact as possible. This does lead to more visible 'grain' in images at higher sensitivities than some other cameras but because this is monochromatic in appearance it is less digital-like, more reminiscent of film grain."

Hopefully this will add a new layer to the understanding of the difference between the two types of noise you've already gained from the other replies. And, it is worth remembering when adjusting noise reduction on your photos.

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