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Author Topic: Noise removal?  (Read 18758 times)
CynthiaM
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« on: June 16, 2008, 08:53:22 AM »
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I recently returned from a trip which included a lot of visits to a lot of beautiful but poorly lit churches.  So I have a lot of images shot with a Canon 20d with high iso (1600, 3200) and of course, a lot of noise.

I'm not sure when in the workflow is the best place to attempt noise removal?  What makes sense is to turn off noise removal completely in camera raw in an attempt to maintain any edge detail.  Or should I do minimal removal in ACR or Lightroom? Once in Photoshop, should I do the noise removal, first, or all my other adjustments and noise removal last, before sharpening?

I am using Noise Ninja for the noise.
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Cynthia Merzer
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« Reply #1 on: June 16, 2008, 09:25:37 AM »
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If you can get away with using ACR or LR's noise removal I would just use that.  (With the 20D I found I rarely needed more than the NR available in ACR/LR at 3200.)  Otherwise turn off sharpening and NR in ACR/LR and do it immediately in CS3 with NN.
« Last Edit: June 16, 2008, 09:25:48 AM by DarkPenguin » Logged
francois
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« Reply #2 on: June 16, 2008, 10:27:47 AM »
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Cynthia,
I perform noise removal in LR or ARC only if I can get rid of it in those tools. For heavy noise removal, I do it in Photoshop using Noiseware or Noise Ninja. In this case, I don't do any capture sharpening or noise removal in LR or ACR. I do capture sharpening after noise removal.
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« Reply #3 on: June 16, 2008, 11:09:35 AM »
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Quote: I'm not sure when in the workflow is the best place to attempt noise removal?


I'm certainly no expert but recently started doing it at the very end in CS3. I roundtrip from LR, apply capture sharpening and then, after any/all tweaks, resize, output sharpen, flatten the TIFF, THEN take care of any noise. I used to adjust noise before the very end but didn't get as good of results. From there, I head back into LR for printing.

HOWEVER, the better looking results MAY stem from the fact that I recently switched from Noise Ninja to Noiseware. They're both quality programs but for whatever reason(s), I'm doing better with the latter.

There are probably many valid reasons why this isn't the best workflow; all I can attest to is better results than before.

Phil
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Andy M
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« Reply #4 on: June 16, 2008, 01:50:23 PM »
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I tend to use Noiseware as soon as the file hits Photoshop.

Why sharpen noise only to soften the file later?
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Gordon Buck
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« Reply #5 on: June 16, 2008, 02:33:19 PM »
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It makes sense to me to apply noise reduction techniques as soon as possible and prior to sharpening.  However, it is my impression that the sharpening process in ACR is different from "sharpening" or unsharp mask in Photoshop.  It seems that the ACR sharpening is considered to be a sort of "capture sharpening".  Therefore, I wonder if there is an optimum blend of ACR sharpening plus 3rd part noise reduction software.

I switched from Neat Image to Noiseware a few weeks ago and find that Noiseware works better for me on my Canon G9 high ISO files.  I don't usually use the G9 at high ISO so have only limited experience with Noiseware.  However, based on a limited number of comparisons, I can't see much difference between retaining or omitting ACR sharpening when Noiseware is applied immediately thereafter.  

I plan to make some additional comparisons because it does seem illogical to sharpen the noise and then try to remove it but I don't know for certain that ACR sharpening actually sharpens the noise in a raw file.
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Philip Weber
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« Reply #6 on: June 16, 2008, 06:38:14 PM »
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I would like to know if ACR/LR and/or PK Sharpener "sharpens noise" as well!

I didn't mention in my earlier post that I use Jeff's PhotoKit Sharpener plug-in.

As stated before, noise removal moved from before to after output sharpening only because of better looking prints but I've also found Noiseware to have a better UI (or at least one I understand better!) than Noise Ninja and so, I have been able to protect the detail better. Working with RAW files, does the process of flattening the file in CS3 after all the tweaks affect noise levels?

As I'm fairly new to digital image processing, I always appreciate the input from the more seasoned photographers out there...that's what makes the LL forum so great for someone with my experience level.

Maybe I should be hitting the noise, flattening the file and then adjusting the image size and performing the output sharpening. I end up saving as a TIFF, with LZW compression, before printing.

OR...maybe I should just say the heck with it, they look good enough to me and spend more time out taking the shots rather than staying at home tweaking them!

As always, I appreciate everyone's insights...
Phil
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gmitchel
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« Reply #7 on: June 17, 2008, 07:23:27 AM »
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I'm going to reply to a couple of threads with one reply.

(1) Sharpening does not add noise. It can emphasize any noise that's already present and take it from being insignificant to very noticeable.

(2) There is no practical way to combine noise reduction with third-party plug-ins and capture sharpening with ACR or LR. Noise reduction should occur prior to sharpening. Noise reduction is antagonistic to sharpening. Capture sharpening is gentle. You are sharpening to restore detail lost from digital capture and no more. That means noise reduction, even with a surface mask, will likely clobber capture sharpening if noise reduction is applied after capture sharpening.

(3) I have not found noise reduction in ACR or LR to be a capable solution for anything but light noise. The Canon 20D is certainly not capable of taking pictures at 1600 ISO with noise light enough that ACR or LR can effectively remove it. I find the 20D to be noisy enough even at 100 ISO to use NeatImage or Noise Ninja for noise reduction in the shadows, sky gradient, etc.

(4) If you do apply noise reduction, it is critical to use a surface mask. You want to keep noise reduction away from the edges. Otherwise you will significantly soften the photograph.

I include a chapter in both my eBook and my video on sharpening because it is so crucial to do it, do it first in the workflow, and to use a surface mask.

You can download free Photoshop tools from the Digital Darkroom of my site for adding masks to photographs, including surface masks.

http://www.thelightsright.com/digital-darkroom.htm

Cheers,

MItch
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DarkPenguin
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« Reply #8 on: June 17, 2008, 07:57:29 AM »
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(3) I have not found noise reduction in ACR or LR to be a capable solution for anything but light noise. The Canon 20D is certainly not capable of taking pictures at 1600 ISO with noise light enough that ACR or LR can effectively remove it. I find the 20D to be noisy enough even at 100 ISO to use NeatImage or Noise Ninja for noise reduction in the shadows, sky gradient, etc.

Really?  I've barely needed NR with my 20D at ISO 3200.
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gmitchel
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« Reply #9 on: June 17, 2008, 08:34:18 AM »
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Really?  I've barely needed NR with my 20D at ISO 3200.
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Really. I only shoot ISO 100 with the 20D unless extreme need compels me to use a faster ISO.

I have owned a 20D for four years. It has less noise than most other cameras from its generation, although more than the 1D MkII, 1Ds MkII, etc. It is very noisy at ISO 3200.

Here's an independent evaluation that is the same result that I see:

[a href=\"http://www.dpreview.com/reviews/canoneos20d/page20.asp]http://www.dpreview.com/reviews/canoneos20d/page20.asp[/url]

Noise is very evident at ISO 800, ISO 1600, and ISO 3200. I have plenty of ISO 100 images in daylight with noise in shadows, sky gradients, etc. Can I remove it. Yes. I use something like NeatImage or Noise Ninja together with a surface mask.

If you cannot see noise at ISO 1600 or ISO 3200 with a Canon 20D, then I respectfully suggest you do not have a trained eye for noise. It does take experience to develop an eye for artifacts like noise. I'm not trying to insult you. I'm just objectively stating that the Canon 20D is not close to noise-free at ISO 1600 or ISO 3200. Not even the 1Ds MkII is close to noise-free at those ISOs.

It is also important to realize that most people resort to such an ISO to get enough shutter speed to handhold the camera. The longer the exposure or the longer the burst of photos, the more heat will build up in the camera and the more noise will be generated.

If you take just one isolated photo at ISO 3200 in broad daylight and use a shutter speed of 1/1000 of a second, you might have *RELATIVELY* little noise. But that's an atypical use of such ISO. The more typical use is a wedding photographer or event photographer trying to use natural lighting indoors with big bursts of photos. Guarantted, the 20D is noisy in that ciurcumstance. If you doubt it, just read any busy wedding forum re. the 20D for weddings.

Cheers,

Mitch
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DarkPenguin
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« Reply #10 on: June 17, 2008, 09:45:29 AM »
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Unless I'm dealing with deep shadows I haven't had any issue with noise that matters in a print.  Perhaps I print smaller sizes than you do.

(Comment only in regards to the Canon 20D.)
« Last Edit: June 17, 2008, 10:27:57 AM by DarkPenguin » Logged
Misirlou
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« Reply #11 on: June 17, 2008, 10:31:50 AM »
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I'm a dinosaur from the film days. I learned digital processing on raw files from my old Canon S50 P&S (which I still use, BTW). Later, I bought a 20D, and now a 40D. But I still go to 6X6 or 4X5 film when I want to shoot something for printing really large.

When I got the S50, noise reduction s/w was sort of new. I found that Neat Image made a massive improvement on S50 files, as one might expect. When I got the 20D, I just kept using the same sort of workflow. I always ran noise reduction, even at 100 ISO, as the very first step after bringing the raw file into Photoshop. I could easily see a big improvement at 1:1 on the monitor. When I got the 40D, I continued with the same workflow.

Things started to get complicated with the arrival of Lightroom. One had to decide where to fit the noise reduction in with capture sharpening. It does not help that you can't confine noise reduction to a masked area in Lightroom.

But it finally dawned on me that it might be useful to see how the noise actually effected prints. Based on my experiments (and keep in mind that I rarely print digital captures from DSLRS bigger than 8X10), noise that seems really objectionable at 1:1 on the monitor may not be meaningful in a (small) print. I think what happened is that I got so used to looking at 5MP shots at 1:1 I that kept doing that with 10MP shots out of habit, even though the 10MP shots require far less enlargement to print.

In any case, I would always do noise reduction as early as possible in the flow. Sharpening will amplify noise, and any sort of color manipulation will operate on chroma noise just as as it will on signal data. No sense in doing any of that if you can avoid it. Lately, I've been running noise reduction in Lightroom, which can handle ordinary 100 ISO noise from a 40D pretty well. Not as well or as controlably as Neat Image in Photoshop, but well enough for 8X10 prints. I'm also running DXO lately, and that does a pretty good job of noise reduction and capture sharpening in one step, although it also suffers from lack of masking.
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gmitchel
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« Reply #12 on: June 17, 2008, 12:14:50 PM »
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But it finally dawned on me that it might be useful to see how the noise actually effected prints. Based on my experiments (and keep in mind that I rarely print digital captures from DSLRS bigger than 8X10), noise that seems really objectionable at 1:1 on the monitor may not be meaningful in a (small) print. I think what happened is that I got so used to looking at 5MP shots at 1:1 I that kept doing that with 10MP shots out of habit, even though the 10MP shots require far less enlargement to print.
[a href=\"index.php?act=findpost&pid=202089\"][{POST_SNAPBACK}][/a]

I think you'll find les need for noise reduction, especially at ISO 400 and below with the Canon 40D. It has much less noise than the 20D.

It is certainly true that print size matters. Noise is likely to be objectionable in a smaller print.

I no not edit at 100% magnification. That is very misleading for assessing noise, sharpening, etc. In the case of a 1Ds MkII or 1Ds MkIII image, you end up with a poster size image at monitor resolution. I use a zoom that approximates print size without lots of aliasing effects. Something like 50% or 25%.

Cheers,

Mitch
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Misirlou
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« Reply #13 on: June 17, 2008, 12:47:34 PM »
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I think you'll find les need for noise reduction, especially at ISO 400 and below with the Canon 40D. It has much less noise than the 20D.

It is certainly true that print size matters. Noise is likely to be objectionable in a smaller print.

I no not edit at 100% magnification. That is very misleading for assessing noise, sharpening, etc. In the case of a 1Ds MkII or 1Ds MkIII image, you end up with a poster size image at monitor resolution. I use a zoom that approximates print size without lots of aliasing effects. Something like 50% or 25%.

Cheers,

Mitch
[a href=\"index.php?act=findpost&pid=202106\"][{POST_SNAPBACK}][/a]

Yes, I agree. I guess I'm still feeling a little burned by certain posters here who insisted a few months ago that the 40D performed no better than the 20D, despite the test shots I uploaded which looked pretty conclusive to my eye. My general experience matches yours.

In any case, to get back to the original poster's question, I feel that noise reduction should be done as early as possible in the workflow. If you can take care of it in the raw converter, great. If not, say high ISO situations, try not to sharpen very much if you can, until you deal with the noise. Just don't agonize over noise too much, because it may not be a big deal in your prints anyway.
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bjanes
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« Reply #14 on: June 17, 2008, 03:31:14 PM »
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I no not edit at 100% magnification. That is very misleading for assessing noise, sharpening, etc. In the case of a 1Ds MkII or 1Ds MkIII image, you end up with a poster size image at monitor resolution. I use a zoom that approximates print size without lots of aliasing effects. Something like 50% or 25%.
[a href=\"index.php?act=findpost&pid=202106\"][{POST_SNAPBACK}][/a]

Judging sharpening on screen is problematic, since the screen is a low resolution device (~90 ppi) and printers have a much higher resolution (typically 300 ppi). At a screen resolution of 25 or 50%, the sharpening halos may not show up. The current version of ACR does not even allow preview of sharpening or NR below 100% and our friend Jeff Schewe suggests that you make the image sharpening look good at 100%. This applies for capture sharpening, so printer resolution is less important than for output sharpening. Still, there appears to be no consensus on judging capture sharpening on screen and comments are invited.

Bill
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« Reply #15 on: June 17, 2008, 04:01:45 PM »
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Judging sharpening on screen is problematic, since the screen is a low resolution device (~90 ppi) and printers have a much higher resolution (typically 300 ppi). At a screen resolution of 25 or 50%, the sharpening halos may not show up. The current version of ACR does not even allow preview of sharpening or NR below 100% and our friend Jeff Schewe suggests that you make the image sharpening look good at 100%. This applies for capture sharpening, so printer resolution is less important than for output sharpening. Still, there appears to be no consensus on judging capture sharpening on screen and comments are invited.

Bill
[a href=\"index.php?act=findpost&pid=202126\"][{POST_SNAPBACK}][/a]

I simply try to go with "no halos".  Sometimes it is "no halos that I noticed.  #$%@!#$%!!"

I'm willing to print with pretty significant halos.
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Misirlou
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« Reply #16 on: June 17, 2008, 05:23:28 PM »
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I simply try to go with "no halos".  Sometimes it is "no halos that I noticed.  #$%@!#$%!!"

I'm willing to print with pretty significant halos.
[a href=\"index.php?act=findpost&pid=202130\"][{POST_SNAPBACK}][/a]

I thought the current theory was that you actually need some halos with inkjet printing to make up for the inevitable ink spread on the paper. That's one of the reasons you sharpen at both the capture and output stages, with entirely different goals in mind, and entirely different sharpening processes.

I'm guessing, based on hints here an elsewhere, that Adobe will be addressing output-specific sharpening in the final release of Lightroom 2.0, and we can all hope they'll be looking at a more sophisticated noise reduction approach too. And don't worry if you aren't using Lightroom, because ACR and Lightroom seem to be cross-pollinating the good ideas of late.
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DarkPenguin
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« Reply #17 on: June 17, 2008, 06:08:06 PM »
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I think that is correct.  But you definitely do not want them at the capture sharpening stage.

Lightroom appears to have some form of pk sharpener available for output.  If I was willing to use it more I'd have more info on it.
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Gordon Buck
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« Reply #18 on: June 17, 2008, 08:52:02 PM »
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It makes sense to me to apply noise reduction techniques as soon as possible and prior to sharpening. However, it is my impression that the sharpening process in ACR is different from "sharpening" or unsharp mask in Photoshop. It seems that the ACR sharpening is considered to be a sort of "capture sharpening". Therefore, I wonder if there is an optimum blend of ACR sharpening plus 3rd part noise reduction software.

I switched from Neat Image to Noiseware a few weeks ago and find that Noiseware works better for me on my Canon G9 high ISO files. I don't usually use the G9 at high ISO so have only limited experience with Noiseware. However, based on a limited number of comparisons, I can't see much difference between retaining or omitting ACR sharpening when Noiseware is applied immediately thereafter.

I plan to make some additional comparisons because it does seem illogical to sharpen the noise and then try to remove it but I don't know for certain that ACR sharpening actually sharpens the noise in a raw file.
[a href=\"index.php?act=findpost&pid=201945\"][{POST_SNAPBACK}][/a]

Replying to myself for continuity ...

I made additional comparisons using my Canon G9 raw files at ISO 400 and 800, ACR with and without sharpening (and sometimes with ACR noise reduction), PK Capture Sharpener, CS3 "Smart Sharpen" and Noiseware.  As a result of these comparisons, I'll be *capture* sharpening in ACR prior to using Noiseware.  

Fully realizing the subjective nature in the compromise between noise reduction and sharpening, I'm simply reporting what I did along with my conclusions.  I also realize that my conclusions are counter-intuitive; however, the results were very obvious.

I've had a full up-to-date copy of NeatImage for several years but have recently found Noiseware more to my liking.  In every comparison, I used Noiseware in the default mode but realize that even better results can be obtained with a little more practice and study.

I've also had and used PKSharpener in the three stage sharpening process for several years.  I believe in this product and procedure but recently have begun to substitute ACR sharpening for PK Capture Sharpen.

For all comparisons, I first made an unsharpened, no noise reduction background image in ACR/CS3.  Then I repeatedly opened the raw file with variations in ACR, processed it and pasted it as a layer over the base background.  I could make comparisons, typically at 50% size and 100% size, by turning layers on and off.  (Got to learn and get confidence in Smart Objects!)

Yes, I know that viewing prints is different from pixel peeping.  I've previously concluded that I can get acceptable -- to me -- 8x10 prints from my G9 at ISO400 with Noiseware.  

In ACR, the sharpening that I'm calling "capture" is mid-range on the Amount - typically 80%, a radius of 1, Detail from 30 to 50%, Mask from 0 to 30%.  I don't claim to be an expert or even to necessarily understand the significance of these numbers -- but I did try a lot of them!

I tried Noiseware on top of ACR Sharpening with ACR noise reduction (lum=80 and color=100) but those were obviously overdone.

I tested the maximums of ACR Sharpening followed by Noiseware.  These were obviously oversharpened but the efffect on noise reduction wasn't as bad as I thought it would be.

I tried zero sharpening and zero noise reduction in ACR followed immediately by Noiseware and then PK Capture Sharpener .  The results were OK but I preferred the ACR sharpening followed by Noiseware.  (Note:  edited 6/19/2008 because the order was transposed in the original posting.)

I tried zero sharpening and zero noise reduction in ACR followed by Noiseware with extra sharpening but didn't that that result as well as with the ACR pre-sharpening.

I tried modest ACR sharpening plus modest ACR noise reduction followed by Noiseware.  Frankly, it was pretty difficult to make a call on some of these.  

Is ACR sharpening that good?  Is Noiseware so good that it makes up for pre-sharpening?  I don't know but am hoping that others will make a few comparisons and report their findings.
« Last Edit: June 19, 2008, 10:47:59 AM by gordonsbuck » Logged

bjanes
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« Reply #19 on: June 18, 2008, 11:51:01 AM »
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Replying to myself for continuity ...

I made additional comparisons using my Canon G9 raw files at ISO 400 and 800, ACR with and without sharpening (and sometimes with ACR noise reduction), PK Capture Sharpener, CS3 "Smart Sharpen" and Noiseware.  As a result of these comparisons, I'll be *capture* sharpening in ACR prior to using Noiseware. 
[a href=\"index.php?act=findpost&pid=202176\"][{POST_SNAPBACK}][/a]

Fine if that works for you, but your approach is contrary to all expert opinion that I have seen. You have not presented any of your results, but I wonder if your testing is sufficiently intensive to reach your conclusion.



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I've also had and used PKSharpener in the three stage sharpening process for several years.  I believe in this product and procedure but recently have begun to substitute ACR sharpening for PK Capture Sharpen.

I tried zero sharpening and zero noise reduction in ACR followed by PK Capture Sharpener and then Noiseware.  The results were OK but I preferred the ACR sharpening followed by Noiseware.

I tried zero sharpening and zero noise reduction in ACR followed by Noiseware with extra sharpening but didn't that that result as well as with the ACR pre-sharpening.

I tried modest ACR sharpening plus modest ACR noise reduction followed by Noiseware.  Frankly, it was pretty difficult to make a call on some of these. 

Is ACR sharpening that good?  Is Noiseware so good that it makes up for pre-sharpening?  I don't know but am hoping that others will make a few comparisons and report their findings.
[a href=\"index.php?act=findpost&pid=202176\"][{POST_SNAPBACK}][/a]

One possibility that you did not test is to do the  capture sharpening in Noiseware. As you know, Noiseware has options for detail protection and detail enhancement. How it does these things under the hood is unclear to me--do they use masks or other algorithms? At least, I would imagine that the NR and sharpening are designed to work together.

I've done quite bit of available light shooting with the Nikon D200 at ISO 1600, where there is quite a bit of noise, even with optimum exposure and Noiseware is my favored program, although I also have NeatImage and NoiseNinja. In his sharpening book, Bruce Fraser pointed out that many noise reduction algorithms produce images that can not subsequently be sharpened without bringing back the noise in full glory. Personally, I found this to be the case with Noiseware and PK capture sharpening. For high volume work in shooting sporting events, I found the best approach was to do the NR and sharpening in Noiseware. This apporoach allows parametric editing, NR, and sharpening in Photoshop with ACR without the necessity of producing intermediate TIFF files.

Bill
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