This is my first and so far only attempt at focus stacking. It's a bit fiddly but easy to do. The strip on the left is the four original shots combined into the one image above. If you open the strip image you should be able to see the four original (unadjusted) shots and their different focus points moving back to front. I really should have used six shots as there is still a region of soft focus in the centre of the apple if you look closely.
I downloaded THIS software from Helicon Focus which is free for 30 days. Very simple to use and brilliant.
Camera D90, Lens 105mm Micro-Nikkor (a 30+ year old manual focus lens, cheap on ebay) Tripod, f16, 1 second exposure.
Lighting? Window on a cloudy day.