A stacked cactus!

Em arrived today and we had a go at focus stacking.  We used the nearest object which happened to be a cactus, a 60ml lens and two extension tubes: 12mm and 20mm.

I took 4 photos with different depths of focus and then used Photoshop CS5 to blend the photos.  The Idea and explanation comes from David Hobbs.  Thank you very much!!

I intend to try this again with better subjects!