Olympus has long been one of the leaders (along with Panasonic) in the mirrorless Micro 4/3 world, but the Panasonic GH line has always been more popular with filmmakers. With the announcement of today's update to the Olympus flagship OM-D EM1 line, Olympus is bringing in more filmmaking features, including options for "cinema" 4K, or video that is 4096 pixels across.
There is a major limitation with the 4K in this camera that might leave some filmmakers frustrated.
Considering that the competitor camera from Canon, the M5, which lives at a slightly higher price point, still shoots 1080 video, having 4K in this camera is great. The ability to choose between 4096 4K and 3840 4kK (otherwise known as UltraHD) is also much appreciated. However, there is a major limitation with the 4K in this camera that might leave some filmmakers frustrated: Both UHD and C4K are limited to the intraframe compressed IPB codec mode only, and the "all-i" video modes most filmmakers prefer are limited to 1080.