The E-M5 Mark II sets a new standard as the digital camera having the most complex and obtuse menu system available, beating out its E-M5 and E-M1 predecessors. OMG
The Olympus OMD E-M5 Mark II produces 9216 X 6912 images (63MP) from 105MB raw files when shot in its sensor shift mode (those dimensions are 2X linear multiples of its 4608 X 3456 native resolution). Or rather, that size when converted using the Olympus plugin for Photoshop. The EM5 Mark II also produces 40 megapixel JPEG images simultaneously (SLF + Raw). Iridient Developer shows a raw file size of 7296 X 5472 (39.9 megapixels, same as the JPEGs).
It’s not possible for me to evaluate critical sharpness on a MacBook Pro Retina with any reliability (the pixels are too densely packed, so fully sharp and not quite sharp are difficult to distinguish), but the raw files appear to contain less actual image detail than the size would suggest. The 40MP JPEGs look relatively good too.
There is certainly “more there” than the native 16MP resolution, but perhaps not in a compelling micro contrast way. My analysis of the realistic gains in detail will have to wait until I’m home and back using my regular NEC PA302W display, to which my eyes are attuned. Moreover, diffraction quickly begins to kill off theoretical resolution gains, with f/8 beginning to look soft (Olympus also does not recommend going past f/8, almost certainly for this reason). Optimal aperture is probably f/4, taking diffraction and depth of field and lens performance all into consideration.
Of course, there can be benefits to oversampling, even if the final output size is no larger in pixels, so resolution should not be taken as the only idea to consider.
Update: Philip Service has an interesting technical analysis (numerical analysis) that correlates strongly with my field analysis: Limits of Resolution. 5. Sensor Shift.