I posted a link to CombineZM in the D.Krakow Auto Repair thread. Rather then hi-jack that thread any further ..
Chuck Doan mentioned - Looks like that Helicon software (or something like it) is the way to go for minature depth of field.
Like I said, I posted a link to download CombineZM (http://www.pcworld.com/downloads/file/fid,84627/description.html) which is a free photo stacking program. It is very easy to use .. but .. here's a Tutorial for stacking with CombineZM software (http://www.redbubble.com/macro-photography/forums/172/topics/12909-tutorial-for-stacking-with-combinezm-software)
I just did a quick and dirty test of the software. The only glitch I ran into was a small strip at the very bottom and left of the stacked photo that appeared to be a mirror of the 'bit' above it. That was simple enough to strip off the finished photo.
Here's the scene using Auto focus at f29
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fi856.photobucket.com%2Falbums%2Fab130%2FLCRRinHO%2FCombineZM%2FZM3_AF.jpg&hash=4a77ac7db65b45846d52baf4b30d7fbc1233e4b1)
Here's the same scene created from 9 photos of varying focus distance using Combine ZM
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fi856.photobucket.com%2Falbums%2Fab130%2FLCRRinHO%2FCombineZM%2FZM3_MF.jpg&hash=1b0f68ac61a395bc744e9774ba9f9b8c1f002802)
Got no complaints .. as hard to beat 'Easy and Free' as Frederic put it.