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.
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.