18 slices tethered
This is the result of some experimentation with the Focus merge software called Helicon Focus.
I set up this pile of surfaces so that the nearest point in the image was just within the closest focusing distance of the 400mm lens.
The aim was to test the software with the very narrow depth of field that will come from focusing so close to a long lens. At this distsnce the acceptable depth of field was about 8mm and the subject, front to back, was about 150mm.
It was not possible for me to accurately judge by eye the focus required for each slice. So I linked the camera to a laptop and set up the tethered shooting software that came with the camera.
It was quite good for camera manufacturers software. I used the tethered shooting program to focus the camera from the laptop, the accurate fine tuning of the focus proved to be very successful.
By the time I had worked from the front to the back of the subject I was older by 5 minutes but I had 18 good slices to be merged.
The program did an excellent job and very little manual tidying up was required.
I am not sure when I might need this procedure in real life, but it is nice to know that it is here & it works.
Still life photographer Graham Jeffery, Hinckley UK.