Optics

So, I was just thinking about microscopic images, and how they're always so much blurrier than illustrations.  I was thinking about how, in videos, you can see various parts of the organism sharply, depending on the focus of the optics... it's just a razor-thin depth of field.

Then I thought: hey, wait, we have HDR photography.  ...Why can't we use this at a microscopic level to increase clarity?

I could even imagine a machine-controlled microscope that produces one image from a composite of multiple images shot at different focal lengths, helping to bring the entire image into maximal focus.

...Of course, I'm sure someone else has already thought of this.