[Jocko]

Today I tried a little exercise from Robin Whalley's book. He is talking about getting to know your camera and the exercise was to try out all the available ISO settings and to see what are acceptable to you, the photographer. I did just that, with my Nikon D80, and was much surprised by the results. The ISO settings on my camera range from 100 to 1600, in one stop increments, then up to 3200 in third of a stop increments. I took the same picture (indoors, as stated in the exercise), then compared them to each other. I have sharpness turned off on my camera (I use Sharpener Pro 3: Raw Pre-sharpener) and for noise reduction I used Dfine 2. This is my usual procedure. I treated each of the raw images, as I normally would, using Lightroom 6.3, then noise reduction in Dfine 2.
The definition and detail dropped off very quickly, with, in my opinion, only ISO 100 and ISO 200 producing quality results. Prior to noise reduction, all settings showed quite a bit of noise in black areas, rising quickly as the ISO went up. The shot was very contrasty, with black to white included, however, the contrast deteriorated very quickly with rising ISO.
The outcome of this is, for quality photographs, I am going to have to limit myself to ISO 100 and 200. If I am desperate I will go up to 400, but anything more than this is really just a waste of time. Maybe I need to do a bit of penny pinching to gather together enough for a more modern camera (with a better sensor system). I would like a Full Frame body, but that, and glass to suit, is way outside an OAP's budget.