Originally posted by Rondec It is when things are really dark that it seems to fall apart. This is iso 12,800 f2.8 and 1/200 second and even doing some noise reduction in post, I don't feel like I could print it at any sort of a decent size. Is it usable? I guess so, but I think it looks pretty poor.
Can I ask what you're using for noise reduction? I get my best results using Lightroom 6. I start by bringing up the black level so there's no clipping of shadows. I tend not to get a lot of this, as in low light situations I aim to over-expose slightly to lower the risk (this is the biggest lesson I've learned recently with low light shooting). I also find that Lightroom has a much wider range of shadow recovery than Adobe Camera Raw. Next, I adjust the white level to address any problematic highlight clipping. If I don't ensure there's no clipping of shadows, then the noise reduction in darker areas will have a very mottled effect. Then, I reduce sharpnening to zero and at 1:1 magnification I adjust luminance noise reduction to a reasonable level (a light amount of grain), leaving color noise reduction at the default of 25. Finally, I typically set the sharpening to around 50 with a radius of between 0.5 and 1.5 depending on how "busy" the subject is, and adjust the masking so that only the edges are getting sharpened - hence avoiding the sharpening of any remaining luminance noise.
I'm sure you know all this anyway, but I thought I'd mention it just in case. I've tried the noise reduction in Pentax Digital Camera Utility, Photoshop Elements 14, Google Nik Dfine 2, GIMP and a few other applications, and while some of them are good, none of them is a match for Lightroom 6 (based on my own experience, that is).
For what it's worth, looking at your photo, I think it's OK. A little further post-processing to increase the clarity and vibrance just a touch might give it a little more punch, but it looks like a pretty natural rendition of the scene...