Upgrading from an E-M10 Mk II to an E-M5 Mk III I was curious to know just how well the in-camera focus stacking works vs manaul focus bracketing with close-ups. In short - not so well. This camera fixes the number of exposures to 8. Fine for landscape but focus close, say 75mm, and 8 exposures are too few. So I ran a test and, with a differenetial of 2 at f8, first with in-camera stacking (8 exposures) then with manual bracketing (16 exposures - reasonable for a close-up). The bracketed set, merged in Photoshop CS6 (old school I know) delivered a sharp band of focus nearly 2.5x that of the in-camera stack. For a 'control' I also merged the 8 exposures used by the in-camera stacking in CS6 and the result was a close match to the in-camera output. Conclusion - E-M5 Mk III in-camera focus stacking is no good for close-ups (and micro and macro). Use focus bracketing.