Focus Stacking with Photoshop

20160827: Step 15 corrected.  

From Wikipedia: “Focus stacking (also known as focal plane merging and z-stacking^[1] or focus blending) is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater depthof field (DOF) than any of the individual source images.^[2][3]”  Focus stacking comes in handy for macro photography which, at high magnification, yields depths of field less than a millimeter.   
 
 There are two ways to photograph each focal plane: by physically moving the camera, and by using the lens’ focus ring.  Physically moving the camera requires a “rack” graduated to fractions of a millimeter, and the good racks cost several hundred dollars.  The focus ring method met my “beginner” requirements.  

 As it turns out, Photoshop (PS) makes the stacking of photos an easy three-phase process.  The following steps apply to PS CS v13, Extended.  

Phase 1: Load each image of the series into its own layer.  

1.    File > Automate > Photomerge
2.    Select the “Layout” as “Auto.”
3.    Turn off “Blend Images Together.”
4.    “Browse…” to load the images.
5.    Press “OK.”
6.    PS now loads the images into separate layers.
7.    When PS finishes Phase 1, proceed to Phase 2.   

Phase 2: Mask the well-focused portions of each image. 

8.     “Select” all the layers.
9.      Edit > Autoblend Layers.
10.    Select “Stack Images.”
11.    Select “Seamless Tones and Colors.”
12.    Press “OK.”
13.    PS now masks the in-focus portions of each image in all layers.
14.    When PS finishes Phase 2, proceed to Phase 3.  

Phase 3: Merge the masked layers into a single, focus-stacked image.  

15.    Layer > Merge Layers
16.    PS now merges the masks from each layer into a single layer.
17.    Save the image in the now merged, single layer as a TIFF.
18.    Voilà!