Technically it's possible with an Olympus camera, static or slow-moving subject, and either continuous lights or fast-recycling strobes. You have in-camera focus bracketing, so you don't need a rail - a tripod is enough, and doing it handheld might be possible. @bvanant did some testing with it underwater and got encouraging results; you can see it here: Bracketing with macroI had missed the focus stacking. Not going to happen.