Ratty Tatty 2

For me there is far too much noise reduction applied to the image. The feathers have lost significant detail and look melted in many areas as a result. Personally "d rather see noise in the image than this plastic look form NR.

The Nikon 300/2.8 is a fantasticall sharp optic, and adding the matched 1.4x converter doesn't take away much sharpness. The resulting equivalent 420mm f/4 optic could easily have been used at f/5.6 instead of f/10 in this situation, allowing the ISO to be dropped to 800-1000. That would have helped a lot with the noise. but bringing up the underside exposure with a curve or any other post processing tool will always make the noise worse.

Can you add an image without NR to see how much noise you started with?

You really got the noise down nicely in this one, David, and the bird has good detail in most areas.  There are a couple of areas like the near wing that have a slightly over-smoothed look, so I think you might have just a bit more tweaking to do, but you're getting very good results.

One thing that I found is that it is much better to use multiple passes of "smart sharpen", set at 3% rather than using "sharpen".  I usually give 2 passes at the full photo size, then reduce the photo size and give one more pass.  It makes a big difference in how much noise shows up.  Nice one, although it would be nice to get a bit of eye contact. 

Once again, there are parts of this image that look really good four iso 2000 and the fact that it's only 22% of full frame.  In the dark areas, one can see some of the disadvantages of the software however, this is still fairly impressive.  I could not do this with my D 500 or with a 800 E.  I suspect a full frame camera definitely does a better job with the DxO optics Pro elite noise reduction system.