Hi Stefan,

You made a good choice with Olympus. As you probably already know the E-M1 I has focus bracketing which you will find really useful for focus stacking.

As for stacking software you could try CombineZP which is free and from which I have recently seen some really impressive results. I did try it myself a number of years ago, but for me it crashed with anything more than about ten shots. Then I discovered Zerene Stacker which I think is the best.

Good luck and hope to see some of your images soon.

Cheers Brian