Micro Four Thirds

Micro Four Thirds is a shared lens mount and sensor size introduced by Olympus and Panasonic in 2008. The sensor measures roughly 17 by 13 millimetres, so the crop factor is 2x and a 25mm lens frames like a 50mm on full frame. The trade is size against light. Bodies and lenses are markedly smaller and cheaper, and in-body stabilisation on these cameras is very good, which suits handheld and travel work. Against that, the smaller sensor gathers less light and holds more depth of field at the same framing, so shallow backgrounds and clean high-ISO footage are harder. Panasonic's GH line and OM System bodies are the video-focused examples.