This is an example of the Macro Photography technique of Focus Stacking. The method is to take precisely focused slices of a subject and stack them together in software. The reason for this is the extremely narrow DoF (Depth of Field) due to a wide open aperture and very close focus. I would surmise that the slices taken in this photo were no wider than 2mm. If that.
This was 33 images blended into one stack.
I used Control My Nikon to make the exposures.
And Adobe Photoshop to blend the images together. I had to do a bit of cleanup in the black areas as there was some ghosting from the white.