Alongside the HDR bracketing modes that recent Olympus cameras have included, the E-M1 becomes the first model able to combine multiple exposures into a single final image. There are two options for this: Mode 1 shoots three exposures and attempts to incorporate the tones in a subtle and realistic manner. Mode 2 takes four exposures and results in a much more extreme version.
Both modes shoot at 'Continuous Hi' speed (10 fps) and make some attempt to auto-align and correct for subject movement, so work pretty well for hand-held HDR shots. In the composite modes the camera will save a single Raw file alongside the combined JPEG, but this only represents the neutral exposure shot. The full HDR bracketing options still exist if you'd prefer to combine the images later on your computer - this will result in better quality overall.
Uniquely, the E-M1 can preview the likely results in the viewfinder, by brightening the shadow areas and balancing the overall tonality. The HDR Modes lock the ISO to 200 and disable exposure compensation, and we've found it's best to meter so that highlights don't look blown in the viewfinder, then let the camera take care of the rest.