One of the things about Photoshop is that the application is SO feature-packed that on a nearly daily basis, I am learning something new about it.
I've always been interested in macro work, but one of the biggest advantages of shooting digital and using the most recent versions of Photoshop is the ability to do "focus stacking," i.e. shooting many exposures of the same subject, but with each shot, slightly varying the focus.
These photos are then loaded into Photoshop and then with a bit of automated magic, the software will blend the in focus parts of each image into a seamless, sharp photo.
If you have Photoshop CC, doing this is pretty easy -- you just load up all the images into it, then go into Automate-->Photomerge and choose all the images you just loaded (uncheck all the check boxes below this).
Next, select all your stacked layers and then go to Edit-->Auto-blend layers and then check the "Stack images" check box in the dialogue box that opens and then wait for the magic to happen.
Nikon D600, AF Micro-Nikkor 60mm f/2.8.