The Olympus OM-D E-M10 III is a 16MP Micro Four Thirds mirrorless camera. It looks like a slightly prettier version of its predecessor and the main changes are to the user interface (UI) and menus, in an aim to make the camera more accessible to relative newcomers to photography.
From a hardware point of view, it's a fairly minor update to the Mark II but the improved ergonomics and UI all have a part to play in making the camera nicer to shoot with and in making some of its smarter... more