Experimenting with Focus Stacking

I have been doing some more experimenting with focus stacking, particularly which is the best focus differential point and where to set initial focus.

Nothing very scientific or a real closeup/macro ,but just to see how it works.

Mounted my E-M1 and 40-150mm on a tripod at about 45 degree downward angle.

Subject is a tape measure on a table. Note tape measure is not completely flat on table as it bends between the edges. Set initial focus point on the numeral 10 at a focal length of 150mm.

Set camera to Manual, SS 1/250 sec, ISO 200, WB Cloudy (Indoor shed with skylight above on a dull cloudy day), A f5.6, , Noise Filter Off.

Sample shots:

Initial focus frame

Focus stacked image narrow setting 1

Focus stacked image narrow setting 3

Focus stacked image mid range setting 5

Focus stacked image wide range setting 10

My observations:

• I found that focus differential point 3 seemed to give the best overall result with most numbers in focus across the range.
• As the focus differential point goes wider the range increases but there a gaps in focus, see wide range setting 10.
• When the images are being taken in focus stacking mode the focus point initiallymoves foward at Frame 2 from the initial focus point. Then moves back slightly foward of the initial focus point. See images below.

Frame 1 with narrow setting 3

Frame 2 with narrow setting 3. See how focus is now near numeral 4.

Frame 3 with narrow setting 3. Focus has now moved back slightly to near numeral 5.

I put together a GIF of the 8 images to see how the focus points change. Hope it works.

This is GIF of the 8 frames changing focus.

Hope this helps and any comments/thoughts on my unscientific experiment are welcome.

Cheers

Dennis