Your best bet would be giving enough light to the shadows, i.e., exposing to the right (ETTR), followed by ACR noise reduction.
Also, limiting yourself to 400 ISO is not the best idea either. You should check out Andrew Rodney's (aka digitaldog) example of 800 ISO being better than 100 ISO. The thread about it is here.
Thanks for this. I have perhaps done the wrong thing by trying to always limit my iso to 400, thinking it would help reduce noise.
That link is "crazy" I have to go back and read it again, and again.
At first it doesn't make complete sense to me.
I understand increasing noise if you are under-exposed (because of low light level and low iso). But if my image is correctly exposed, and still exhibits noise at a low iso, then what is it - small sensor, sensor heat build up, slow shutter speed, ...?
But re: managing noise - your advice is to do it in ACR. Good, thanks.