I'm working on background control. Many pics posted here (& everywhere) have a 100% black background. Right now I'm shooting outdoors, on static subjects, & I can sometimes blur out a background, if I can get in close, by stopping aperture down to around f/16 then adjusting shutter speed (& ISO if necessary) for good exposure; but so far nothing close to "all black". Also if I use max zoom to get tighter to the subject the resulting images can look flat & grainy without much subject isolation. At this stage I want to achieve as dark as possible in camera. I figure if I can do that whenever I want, I can get any amount of bokeh, or subject isolation I want, for any shot.

I've been searching posts but haven't pieced it together yet. Some posts mention using f/16 or higher to black out a background. Some posts mention using shutter speed to do this (but no specifics). Some posts mention diffraction countering depth of field effects at apertures above f/11. Some tutorials I've read on this topic seem aimed at studio work.

I have a D7200; Nikkor 18-140 & 70-300 VR's; Sigma 17-70 & Tokina 11-16. So far I've only tried this effect with the 2 Nikkor lenses as I have no hoods for the other 2 (& limited lighting for shooting indoors).

Is there a straightforward approach to crisply isolating a static subject, outdoors, with a black or quite dark background (including indoor vs. outdoor)?

I've used a black velvet cloth attached to a piece of cardboard for a dark background. But time and time again, the masking approach nails it with the least amount of fuss. Both Photoshop and On1 provide tools to retain difficult details, like slightly out of focus wisps of hair, fur and other difficult situations. I agree, Topaz's solution was hard to work with and the results were seldom worth the effort.

I use both methods - hand selecting and manipulating the selection, and with masks - which, of course, begins with making a reasonably clean selection. I don't think we disagree at all. But I stop at assuming that masking is beyond the capability of the OP, and would rather encourage her to take a look at the process and possibly try it out. Both software titles I provided links to have 30 day free trials, so she can certainly check either out to see if this will do what she needs. I applaud her curiosity and openness to learning new stuff.

The aperture and shutter speed numbers don't matter specifically; it's simply your overall exposure and light source. What kinds of subjects do you want to isolate via a dark background?

Bokeh and background blurring is a separate discussion (and dependent on the lens and the aperture setting, among other considerations).

Shooting subjects that are sunlit while backgrounds are in shadow will make it much easier (as will shooting in raw for additional adjustments of blacks) - one of the many reasons I prefer early morning photography

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