Re: Focus stacking.

This is the part where I get to link my duck stacking .gif. Again!

This is far from macro, so there were only like, eight (?) relevant exposures in this stack. But you are correct in that high magnification photos taken very close to the objective can require dozens or maybe even a hundred exposures to get everything in focus.

This small ballpoint pen tip was I think around 40:

And this top-down view of the edge of a strange knife (of course) I think was pushing 100:

The texture in the backdrop there is that of an ordinary sheet of printer paper, lit obliquely with a small flashlight.