Noise Redution ACR....

[Phil-D]

Hi, Took the image below the other night. Its was shot in raw, after a few tweaks with the sliders in ACR I slid the luminance to 80 and the noise had more or less gone, the dark sky looked great.

when I converted it back to j-peg in E11 quite a bit of the noise looks to be back again

In the j-peg options box I save as quality 10, maximum, baseline standard. Now I have to confess to not actually being able to explain what these setting are, but they're what I've always used and never really noticed the return of noise before

Looking at a lot of other folks night shots, the black sky is nearly noise free, like this shot was in ACR before I convert to j-peg .....Am I missing something obvious

cheers


Brimham Rocks by Phil D 245, on Flickr

 

[redhed17]

Not sure why the noise came back in the saved Jpeg. When you open the RAW file back up again in ACR, are the Noise Reduction settings the same, and does it look 'noise reduced'? There is a chance that the noise reduction setting were somehow reset before saving.

As an aside, even though when you click on the maximum jpeg quality setting it changes to 10, you can actually save as a quality setting of 12. Why does it set 10 as the maximum? I don't know. Will you be able to see the difference between 10 and 12? You'd have to check. I always save mine at 12 though.

 

[petersmart]

What you have isn't noise but the artifacts of the NR process.

You can also see the effects of that NR in the rocks and the grass where they are unnaturally smooth in places.

In may cases this can't be avoided and often goes unnoticed and not much can be done about it apart from using a lower ISO and a longer exposure time or a different NR program.
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[Phil-D]

Not sure why the noise came back in the saved Jpeg. When you open the RAW file back up again in ACR, are the Noise Reduction settings the same, and does it look 'noise reduced'? There is a chance that the noise reduction setting were somehow reset before saving.

As an aside, even though when you click on the maximum jpeg quality setting it changes to 10, you can actually save as a quality setting of 12. Why does it set 10 as the maximum? I don't know. Will you be able to see the difference between 10 and 12? You'd have to check. I always save mine at 12 though.

Thanks for reply, Yes, if I open the raw file back up in ACR it looks ok and settings are just as I had adjusted them ......I think 10 must be set as default, yes I'd noticed that I could go up to 12 (sorry, it was badly explained when I said 10 maximum) haven't tried saving as 12 but I'll give it a go

What you have isn't noise but the artifacts of the NR process.

You can also see the effects of that NR in the rocks and the grass where they are unnaturally smooth in places.

In may cases this can't be avoided and often goes unnoticed and not much can be done about it apart from using a lower ISO and a longer exposure time or a different NR program.
.

Thanks Peter .....I see what your saying in that I've created it by trying to get rid of noise in the first place ....what I was confused by was that it looks ok as a raw file but not when converted to j-peg.......if I understand right, your saying its the actual converting to j-peg that makes it visible and there's not a lot can be done about it?

 

[haggis]

Will it be any better if saved as a TIFF?



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[petersmart]

Thanks Peter .....I see what your saying in that I've created it by trying to get rid of noise in the first place ....what I was confused by was that it looks ok as a raw file but not when converted to j-peg.......if I understand right, your saying its the actual converting to j-peg that makes it visible and there's not a lot can be done about it?

I don't have ACR, I use Neat Image instead, but no it's the actual NR process which creates them so no matter how you saved them they will still be there.

Will it be any better if saved as a TIFF?

You could try but I doubt if it would make any difference - I believe (though someone may correct me on this) that these artifacts are actually a result of the Bayer mosaic used on all sensors (except Faveon sensors).
I believe that the mosaic is such that normal NR cannot remove all the noise and leaves behind visual traces of the mosaic which appears as the artifacts you have.

I myself have tried a great many experiments with NR trying to retain detail while getting rid of noise and have come up against these artifacts (which all look roughly the same) many times whether using RAW, JPEG or TIFFs, usually as a result of using a high ISO and applying too much NR.
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