Noise reduction has been a strong interest of mine for years. I've used Neat Image since 2007 or early 2008, and have upgraded regularly. I currently have installed on my system:
- Neat Image
- DxO's newest "Prime" NR,
- several different FFT routines (including several in Matlab and Mathematica),
- Imagenomic's Noiseware,
- the current NR in ACR and LR
- Medhi's Noise Shampoo
- NIK's Dfine
- Power Retouche Pro's Noise Corrector
- Tiffen's DFX v3 DeNoise (under "Image")
- the latest version of Topaz DeNoise
- XiDenoiser
My current recommendations are:
a. For de-noising of RAW files from common cameras, DxO's Prime is heads and shoulders above everything else. My second choice for RAW files would be, believe it or not, the NR built into ACR and LR. If you are a photographer, de-noising the raw, by almost any method will almost always be better than denoising the image after conversion to a conventional bitmap. That being said, a bit of initial de-noising of the raw file, followed up by a 2nd round de-noising later in one's workflow is sometimes the best approach, particularly, if you want the file in different sizes.
b. For removal of texture, even though I've been a huge supporter of Neat Image for years, it's a distant 2nd to the manual FFT approaches. But, when you are in a hurry, have to get something out the door fast, and don't have time to devote to the task (manually), it's better than anything else (except FFT'ing the image).
c. For general de-noising of images once inside of PS (ie, it's no longer a raw file), it's a neck-and-neck race between XiDenoise (extraordinarily versatile, many different algorithms, a geek's dream, LOL, and the best on popcorn noise), DxO's Prime, Neat Image, & Noiseware (for portraits).
d. IMHO, at the bottom of the heap are: Medhi's "Noise Shampoo", PRP's "Noise Corrector", and Tiffen's DeNoise. They all certainly can reduce noise, but often at the price of loss of detail and/or a fake plastic look.
e. IMHO, somewhere in the middle of the pack are NIK's Dfine and Topaz's DeNoise. Both are nice, competent, general purpose products, just not superstars in any area.
Also,don't forget that when evaluating NR tools, it's not simply the amount of noise reduction that's important -- it's the amount of de-noising AT A GIVEN LEVEL OF PRESERVATION OF REAL IMAGE DETAIL. Also, the artifacts produced by the above algorithms are all different. For example, in 2007-2008, when Neat Image was, IMHO, the one-to-beat, if you cranked it up too high, it could produce weird little worm-like artifacts. Fortunately, I haven't seen them in years, LOL. Similarly, if you are not careful, FFT's can easily introduce ringing artifacts (eg, light and dark halos, as well as wide, smooth light and dark bands). Only you can decide which type of artifact you can live with.
HTH,
Tom M
PS - At the risk of stating the obvious, if you are the one taking the picture and your subject is stationary, the best noise reduction is to put your camera on a tripod, drop the ISO to the lowest setting on your camera, and just take a long exposure, or use flash (if that's possible). The results of a shot at low ISO will always be better than using a higher ISO and hoping that some magic NR software will come to the rescue in PP.