Focus stacking in photography is a technique used to get the greatest amount of depth of field in a single image by processing multiple images taken at different focus distances. Most of the time we are talking a handful of images. Probably less than 10 for most people. Now all of that changes when you start doing micro photography and use microscope lenses to get your final images.
The video below is about the groundbreaking photographic technique used by Levon Biss for the Oxford University of Natural Sciences. Biss focus stacks as many as 8000 images, moving his camera 10 microns at a time to get his end result. A human hair is about 75 microns, so Biss is moving his camera about an eighth of the width of a human hair to get enough shots to build a final image. The reason for this is because the depth of field on the lenses he is using is so shallow, it is the only way he can produce the results he wants. And those results are pretty damn amazing.
I don’t really get into insects, but I could look at this stuff all day long. Be sure and jump over to his site to see more of this amazing work.