wthomson wrote:
... still need to know how many stops I can anticipate gaining with current quality noise reduction software and technique....
Sorry, but only you can answer that question. There are simply too many variables.
If you do a search for reviews of your particular camera you will likely find some comparison of noise levels at different ISOs. That might help a bit.
But ultimately it will depend upon...
1. How you'll be using your images... an image displayed online or printed relatively small might be able to get by with a lot more noise than some "higher" use demands.
2. What level of noise you personally find tolerable.... everyone forms their own opinions about noise, how much is too much, etc.
3. Conditions at the moment of exposure and the subject being photographed.... for example noise is much more tolerable or "hidden" when photographing a furry or feathered subject, than it is with something that's a smooth tonality. Noise also shows up more in shadows than in lighter toned areas.
4. How careful you are about exposure accuracy, especially avoiding under-exposure, which when corrected in post-processing very likely will increase the appearance of noise.
Things you can do...
Shoot RAW to be sure you have as much original image data as possible to work with in post-processing.
Minimize cropping of your images. In other words, do your best to "fill the viewfinder" with your subject. Any cropping will increase the appearance of any noise that might be present.
Shoot a series of test shots with your camera, at all the ISOs it can do or at those you think you might want to use... then closely compare them yourself. Ultimately only you can decide what's usable and what's not... so this is important.
Be sure your software is as up-to-date as possible. A lot of the more recent improvements in noise handling seem to be coming from software, rather than from hardware development.
Use some form of noise reduction. Like some others, I often use Noiseware ($80 as a Photoshop plug-in, but I think also available as a stand alone). Depending upon the particular images, I also sometimes use other noise reduction software. For example, a camera manufacturer's own RAW conversion software might be particularly well-tuned to correcting the noise produced by their particular cameras. For example, I shoot with Canon and used to use their software for my highest ISO images, before the noise reduction was improved in more recent versions of Lightroom and Photoshop, and before I had Noiseware installed and learned to use it. I now rarely use Canon's own software because the others have improved to match or beat it. I've also installed Nik DFine (freebie, another Photoshop Plug-IN) but haven't used it much... doesn't seem nearly as advanced as Noiseware.
Be careful about your workflow. I always do noise reduction before any sharpening, for example. When an image is sharpened, it will make any noise that's present become more apparent. So I do my best to get rid of noise first. Depending upon what you're doing with the image, it also is usually best to do noise reduction before down-sizing an image for printing or other purposes. Probably would be best to do it before scaling an image up in size, too... if ever doing that.
Sometimes an image can be "saved" by converting it to black & white or sepia toned, where any noise looks more like film grain and is far less objectionable.
Go ahead and shoot! Take the shot, regardless. This applies to anytime you're shooting near the margins of what's possible. Maybe only one or a few images will be usable, while others are trash. But isn't it better to have one or two than none at all?
When you have time, take additional shots at different settings... higher ISO with faster shutter speed, lower ISO with slower. Some people just keep firing away without varying their settings at all. If one image isn't usable, then all of them aren't going to be usable. Or, they end up with a whole bunch of duplicates. They might surprise themselves if they'd just "try other things"... various shutter speeds, apertures and ISOs (among other things).
Sometimes you can get by with slower-than-you-think shutter speeds, too... even when hand-holding. Use something to steady your shot, such as leaning against a tree or rock or whatever. Set your camera to high continuous rate and take a burst of shots, increasing the odds of at least one shot coming out well even at "too slow" shutter speeds. I don't know the specifics of yours, but most cameras now have some form of bracketing that might be useful for this purpose.
Hope this helps!