I used the Ricoh SDK and added a function to the CLI program to take a series of shots, changing the focus point each time. I enter the number of steps I want, both before (stepsFront) and after (stepsBack) the natural focus point, and the size of the steps (stepSize) and then call the functions to perform the sequence:
First focus normally with the Focus() function
Call StartLiveView()
Call AdjustFocus() to move the focus stepsFront * stepSize so the focus is at the start of the desired range
Then loop over the range
{
CaptureWithoutFocus
AdjustFocus stepSize
}
Stop LiveView
The AdjustFocus function only works in Live View.
It works pretty well. I stack the shots with Zerene.
Cactus flowers | Focus stack using Zerene | Graham Dicker | Flickr