The point of focus stacking, is to have your image sharp throughout.  Most of you have seen landscapes, etc, with soft foregrounds or backgrounds, which would benefit from this technique.  Also some macro images.  To prepare for this, you must use a tripod, and a remote or cable shutter release when shooting.  The camera absolutely cannot move during capture.  Use a minimum of F16 for landscapes and F8-F11 for macros.  Leave some room for cropping later.  Focus manually, taking anywhere from 2 up to 30 images depending on your subject.  And naturally, your subject needs to stay put.

Prepare your series of RAW files in ACR as a batch (to keep exposure, etc, uniform throughout), and convert to TIF.  Give your batch a name, Photoshop will automatically number them.  Do not do any cropping yet.  Back in Bridge, shift/click to select all.  Double click on 1 to move them all into PS, and stack them in the window.

File>Scripts>Load Files into Stack>Add open files>OK

Shift/click on the layers in the layers palette to select all

Edit>Auto Align Layers>Auto>OK

Edit>Auto Blend Layers>Stack Images>OK  (this can take a little while, depending on how many you are using).

If you are satisfied with the results, then flatten the image (to get rid of the "cracks"), and you will need to crop a little, to clean up the edges.  Do a "save as", and rename the new image.  Then finish editing as desired.

Many times with macro images, there will be edges that don't line up.  No matter how careful you are, as you change focus, it changes the size of the image slightly as edges blur in and out.  You will have to clean it up a little.  I've heard that CS5 has improved this.  Helicon Focus still does the best job so far.  The Photoshop method works well with landscapes and architectural images, not as well with macros.

Respectfully submitted,

Melanie Marts