I can see from that - that i have been totally wrong in my thinking of aperture. I always thought that it would be better to be at a very small aperture to have a photo very sharp. So now I understand that it would be better to be at the sweet spot say - f/8 - to bring my landscape photos in more sharp focus - understanding that infinity may be soft if you go to that depth of field? The more I read the more I think this all relates back to the concept of hyperfocal distance.
The "rule" of one or two stops down from maximum is the "sharpest aperture" is correct most of the time. This rule is especially true for less expensive lenses. However I have discovered that once you discover the sharpest aperture the lens will be equally sharp for several additional settings. For example I have a lens that has a maximum aperture of f/5.6, so applying the above rule, this lens should be sharpest starting at f/11.0. In reality it may be a little less or a little more - experimenting would be the only way to find out for sure.
Well, technically....you do get the most sharp image at F/8....but only in the part where it is in focus!
It's a tradeoff between DOF (the area that is in focus), and overall sharpness.
It took me a long time to understand this - and you are totally correct. Now I have to make the decision on DOF or sharpness in my photographs.